binning, f-ratio, pixel-scale, drizzle, onag vs oag and the consequences for my next imaging setup

Topic starter

Dec 15, 2024

Fellow friends of the night sky,
Just two months ago, I opened a thread asking for your opinions on which scope to buy.
Today, I’m back with a similar goal. I’m willing to invest a significant amount of money to either complement or replace my existing Esprit 120.I’m quite happy with my Esprit. I like its image quality, it’s light enough to be portable, and it doesn’t give me too many headaches.
However, what I don’t like is the scope’s speed. After roughly four years in this hobby, I can confidently say that I’m addicted to a good signal-to-noise ratio. I have Bortle 3–4 skies, and even with 40ish hours of exposure time, it often feels like it’s not enough to achieve my goals.I’m considering keeping the Esprit as a wide-field scope, paired with the 0.77 reducer and an ASI6200-sized chip. However, I definitely want a scope combination that allows me to capture quality data more quickly.
What I know I want:

A dual setup consisting of two identical scopes mounted on separate mounts (most likely two EQ6-Rs, or possibly CQ350/EQ8s).
Pixel scale suitable for typical Central European seeing conditions (0.5–1"/pixel).
Portability—the scopes must be small and light enough to carry from my house to the garden. Any scope manageable on an EQ6-R Pro should be fine.
Speed—enough (combined) speed to go deep reasonably fast.
Back focus—sufficient to accommodate an imaging train with an electronic rotator, OAG, filter wheel, and camera.
Image quality—good enough for at least APS-C-sized chips.
Ease of use—I don’t want to collimate the scopes every night.

Thanks to the tips I received in my last thread, I now have two setups in mind that I think would work well

ption 1:2x Lacerta 200/800 + GPU Coma Corrector / APM 1.5x Coma Correcting Barlow

IMX571M = 0.97"/pixel resolution with the GPU or 0.65"/pixel with the APM 1.5 Barlow.

Option 2:2x EdgeHD 9.25 at native focal length

IMX455M = 0.66"/pixel resolution using Bin2.

Both setups offer similar light-gathering capabilities and achievable fields of view. The Lacerta GPU combo would allow for a wider FOV, which is appealing and might even make me sell my Esprit since it would meet my wide-field needs.

Where I’m stuck:

EdgeHD speed and pixel scale

Detail with the Lacerta 200/800

High-resolution imaging and guiding

I’m personally leaning toward the Lacerta setup. My main hesitation is the need to swap the GPU for the APM 1.5 whenever I want to image smaller targets. I dislike making these kinds of adjustments—much like how I own the 0.77 reducer for the Esprit but rarely use it. On the other hand, using only the APM and skipping the GPU feels like I’d be sacrificing potential speed. The lacerta setup also would be cheaper than the edge hd setup, especially as I would need full frame chips using bin2 (to little fov and mp left using apsc)

Thanks for reading, and I’d love to hear your thoughts on these (or other) setups!Clear skies,
Anderl

Well Written Engaging

andrea tasselli

Frequent contributor

Dec 15, 2024

You would rarely go below 2" fwhm and mostly in summer so for all practical aspects a pixel scale between 0.7" and 0.9" would fit the bill. Given that, can you use a guider scope for the best seeing? Yes, if it is properly set up with the right image scale to match the one you are imaging with, i.o.w. not a tiny finder-scope. I have done it because I had and still have refractors to spare. I'd go for a larger scope rather than a brace of two smaller ones for matters of massively more efficient spending but if I were to go dual the I'd rather get a Paracorr and be done with it, image scale should be up to scratch (0.84"/px) and you wouldn't have to swap set-ups. Can drizzle replace real focal length? No, for most of the times when drizzle makes sense. There are occasionally instances when it DOES make sense, when significantly under-sampled and with intrinsically high SNR frames, i.e. with intrinsically bright subjects (and there aren't many of them around).

Anderl

Topic starter

Dec 15, 2024

andrea tasselli:
You would rarely go below 2" fwhm and mostly in summer so for all practical aspects a pixel scale between 0.7" and 0.9" would fit the bill. Given that, can you use a guider scope for the best seeing? Yes, if it is properly set up with the right image scale to match the one you are imaging with, i.o.w. not a tiny finder-scope. I have done it because I had and still have refractors to spare. I'd go for a larger scope rather than a brace of two smaller ones for matters of massively more efficient spending but if I were to go dual the I'd rather get a Paracorr and be done with it, image scale should be up to scratch (0.84"/px) and you wouldn't have to swap set-ups. Can drizzle replace real focal length? No, for most of the times when drizzle makes sense. There are occasionally instances when it DOES make sense, when significantly under-sampled and with intrinsically high SNR frames, i.e. with intrinsically bright subjects (and there aren't many of them around).

thx andrea ;)

i initially planed to go with the 8 inch lacerta paired with the paracorr. The seller adviced against the combo because the necessary spacing would put unnecessary pressure on the oaz. I of course could go with for example an ts ontc newton that works better with paracorr.
is there a general opinion on lacerta vs ontc?

i also thought about going bigger but i fear that a 10inch or bigger newton would make setting up unnecessarily hard. I also could probably not successfully use my eq6r.
a 12 inch f4 newton combined with a starizona nexus would get me the resolution and speed i am looking for but is really big and heavy and i am not sold on the nexus reducer/corrector. Looks like a lot of people have problems collimating using it.

Álvaro Méndez

Dec 15, 2024

Hi Anderl,

Considering you have a garden, have you thought of the possibility to have the scopes permanently out? I own two telescopes and I have them all year round in my garden with a geoptik cover and a rope around. It might rain, pour, blow or snow that my equipment is protected.

In fact, I wouldn’t be able to have my 12-inch if I had to move it every night, it is very very heavy. You’re probably thinking “someone’s gonna steal your equipment”. In my case that is not very likely, this is a very isolated little town, maybe in a different area… and I don’t mind the risk in exchange for total convenience. It’s plug and play.

When there are stronger winds I place tighter ropes and that’s all. This way you might consider a 12 inch newtonian which would be impossible otherwise.

Helpful Engaging Supportive

Anderl

Topic starter

Dec 15, 2024

Álvaro Méndez:
Hi Anderl,

Considering you have a garden, have you thought of the possibility to have the scopes permanently out? I own two telescopes and I have them all year round in my garden with a geoptik cover and a rope around. It might rain, pour, blow or snow that my equipment is protected.

In fact, I wouldn’t be able to have my 12-inch if I had to move it every night, it is very very heavy. You’re probably thinking “someone’s gonna steal your equipment”. In my case that is not very likely, this is a very isolated little town, maybe in a different area… and I don’t mind the risk in exchange for total convenience. It’s plug and play.
When there are stronger winds I place tighter ropes and that’s all. This way you might consider a 12 inch newtonian which would be impossible otherwise.

Hey Alvaro,

thx for your answer.
my mount stays out covered in a similar way as yours, my scope comes in once there are a bunch of bad weather days.
My garden is very private as well and i don’t really fear that my gear gets stolen, i mean who could steal a 12 inch anyway

I am not sure if a quality scope would be fine with the following, maybe it would be no problem, but my gear is very exposed to wind and we have multiple days/nights a year where the wind reaches upwards of 100km/h.
my mount does not care but would a 12 inch newton?

andrea tasselli

Frequent contributor

Dec 15, 2024

Anderl:
thx andrea ;)

i initially planed to go with the 8 inch lacerta paired with the paracorr. The seller adviced against the combo because the necessary spacing would put unnecessary pressure on the oaz. I of course could go with for example an ts ontc newton that works better with paracorr.
is there a general opinion on lacerta vs ontc?

i also thought about going bigger but i fear that a 10inch or bigger newton would make setting up unnecessarily hard. I also could probably not successfully use my eq6r.
a 12 inch f4 newton combined with a starizona nexus would get me the resolution and speed i am looking for but is really big and heavy and i am not sold on the nexus reducer/corrector. Looks like a lot of people have problems collimating using it.

I'd think the consensus is that they can be of equal quality but with an edge on the Lacertas in terms of consistency in quality. On the flip side they are harder to obtain, so there you go. I can't see any issue with the Paracorr but I DO see issues with the GPU (sticking out into the light path and being too long for most focusers) as I have one.

My strong advice is to get a larger scope rather than two smaller ones, that is a recipe for nightmares in balancing, collimating and aligning the two tubes together. I'm imaging with a 12" but much heavier than the present offering for either TS or Lacerta, in part due to having a rather large guide scope. Obviously that is not something you can put on an EQ6R. At any rate I can put it on my mount with a single hand (actually arm) so I expect a 10" f/4 is entirely feasible and probably may still work fine with your current mount.

Whatever your final choice will be realize that:

1. Add a tilt corrector device (either as third party or embedded) into the imagining train. THAT is going to be critical for most set-ups and for Newtonians in particular.

2. A rotator requires (again, for most set-ups but for Newtonians in particular) the capability of taking flats in whatever orientation your imaging train is clocked to, which means that it needs to be automated and controllable by the acquisition program since it'll be needed to work just before or after the session is done and before changing orientation again. This said I hate rotators and I never had them. Budget for these automated flat panels too, considering their outlay for a dual setup.

Helpful

Tobiasz

Dec 15, 2024 · Edited: Dec 15, 2024

Álvaro Méndez:
Both setups offer similar light-gathering capabilities and achievable fields of view.

Hi,

how are they similiar? At the same sampling rate of ~0.66"/pix the double EdgeHD + BIN 2 setup collects much more signal per pixel than the newtons with the barlow and BIN1. In general, because of the larger aperture you catch more photons from the DSO.

If you type in the rough numbers: Calc

Aperture: 235mm vs 200mm
F ratio: f/10 vs f/6 (Newton with Barlow)
Obstruction: 33% vs 36% (internet numbers I googled)
Pixel Size: 3.76 vs 3.76
QE: 85% vs 85%
Bin: Bin2 vs Bin1
I kept out the pixel count, because from a light gathering standpoint it is not relevant. You already know the FOVs are about the same.

# Telescope 1 f/10.00 fl=2350mm D=235mm O=33% res=0.66"/p FOV= 5.5'x 5.5'= 0.26x eoi= 0.36x poi= 0.50x e= 0.37x pe= 1.46x ps= 1.46x os= 1.40x
# Telescope 2 f/ 6.00 fl=1200mm D=200mm O=35% res=0.65"/p FOV=10.8'x10.8'= 3.84x eoi= 2.78x poi= 1.98x e= 2.74x pe= 0.68x ps= 0.68xos= 0.71x

Each pixel in the EdgeHD setup receives about 1.5x times more signal than in the lacerta setup. So I would definetly vote for the EdgeHD setup.

But the "speed" comes at the cost, that your mount and guiding has to be really good for this to work. OAG will be a must have.

CS

Helpful

Anderl

Topic starter

Dec 15, 2024

Tobiasz:
Álvaro Méndez:
Both setups offer similar light-gathering capabilities and achievable fields of view.

Hi,

how are they similiar? At the same sampling rate of ~0.66"/pix the double EdgeHD + BIN 2 setup collects much more signal per pixel than the newtons with the barlow and BIN1. In general, because of the larger aperture you catch more photons from the DSO.

If you type in the rough numbers: Calc

Aperture: 235mm vs 200mm
F ratio: f/10 vs f/6 (Newton with Barlow)
Obstruction: 33% vs 36% (internet numbers I googled)
Pixel Size: 3.76 vs 3.76
QE: 85% vs 85%
Bin: Bin2 vs Bin1
I kept out the pixel count, because from a light gathering standpoint it is not relevant. You already know the FOVs are about the same.
# Telescope 1 f/10.00 fl=2350mm D=235mm O=33% res=0.66"/p FOV= 5.5'x 5.5'= 0.26x eoi= 0.36x poi= 0.50x e= 0.37x pe= 1.46x ps= 1.46x os= 1.40x
# Telescope 2 f/ 6.00 fl=1200mm D=200mm O=35% res=0.65"/p FOV=10.8'x10.8'= 3.84x eoi= 2.78x poi= 1.98x e= 2.74x pe= 0.68x ps= 0.68xos= 0.71x
Each pixel in the EdgeHD setup receives about 1.5x times more signal than in the lacerta setup. So I would definetly vote for the EdgeHD setup.

But the "speed" comes at the cost, that your mount and guiding has to be really good for this to work. OAG will be a must have.

CS

Hey Tobiasz,

thx. This brings me to my concern number 2. is cmos binning that effective that my f10 becomes f5 or do i lose signal somehwere?
oag would be no issue with the edge setup, and my tuned eq6r pro should also be up to the task. At least i would think so.

andrea tasselli:
Anderl:
thx andrea ;)

i initially planed to go with the 8 inch lacerta paired with the paracorr. The seller adviced against the combo because the necessary spacing would put unnecessary pressure on the oaz. I of course could go with for example an ts ontc newton that works better with paracorr.
is there a general opinion on lacerta vs ontc?

i also thought about going bigger but i fear that a 10inch or bigger newton would make setting up unnecessarily hard. I also could probably not successfully use my eq6r.
a 12 inch f4 newton combined with a starizona nexus would get me the resolution and speed i am looking for but is really big and heavy and i am not sold on the nexus reducer/corrector. Looks like a lot of people have problems collimating using it.

I'd think the consensus is that they can be of equal quality but with an edge on the Lacertas in terms of consistency in quality. On the flip side they are harder to obtain, so there you go. I can't see any issue with the Paracorr but I DO see issues with the GPU (sticking out into the light path and being too long for most focusers) as I have one.

My strong advice is to get a larger scope rather than two smaller ones, that is a recipe for nightmares in balancing, collimating and aligning the two tubes together. I'm imaging with a 12" but much heavier than the present offering for either TS or Lacerta, in part due to having a rather large guide scope. Obviously that is not something you can put on an EQ6R. At any rate I can put it on my mount with a single hand (actually arm) so I expect a 10" f/4 is entirely feasible and probably may still work fine with your current mount.

Whatever your final choice will be realize that:

1. Add a tilt corrector device (either as third party or embedded) into the imagining train. THAT is going to be critical for most set-ups and for Newtonians in particular.

2. A rotator requires (again, for most set-ups but for Newtonians in particular) the capability of taking flats in whatever orientation your imaging train is clocked to, which means that it needs to be automated and controllable by the acquisition program since it'll be needed to work just before or after the session is done and before changing orientation again. This said I hate rotators and I never had them. Budget for these automated flat panels too, considering their outlay for a dual setup.

1. i really appreciate your opinion andrea.
If using an guide scope i will probably find place for an tilt plate.

2. this is something i have not thought to much about until now. With my apo it does absolutely not matter, at least not the point where it significantly would reduce my image quality. I can use one set of flats for alls my lights and only redo them like once every six months

Tbh i am having quite a hard time understanding the following but, as long as i don’t move the newton within its rings the usage of an electronic rotator and plate solving every night and after every flip should perfectly align the spikes every time? Am i right? I am not sure

A single set of lights for multiple imaging sessions should work in regards to dust and spikes but i am honestly have never thought about an maybe uneven illumination or differing collimation? Over the course of multiple nights to multiple weeks or even months.
is it really necessary to redo flats every night and orientation for every filter using newtonians?

thx for the headache andrea ;)

andrea tasselli

Frequent contributor

Dec 15, 2024

Tobiasz:
Each pixel in the EdgeHD setup receives about 1.5x times more signal than in the lacerta setup. So I would definetly vote for the EdgeHD setup.

*Not with my calcs, it is more like 34% more than a 8" f/4. But RON is twice. With dark skies and faint targets that is going to matter.

Álvaro Méndez

Dec 15, 2024

Anderl:
Álvaro Méndez:
Hi Anderl,

Considering you have a garden, have you thought of the possibility to have the scopes permanently out? I own two telescopes and I have them all year round in my garden with a geoptik cover and a rope around. It might rain, pour, blow or snow that my equipment is protected.

In fact, I wouldn’t be able to have my 12-inch if I had to move it every night, it is very very heavy. You’re probably thinking “someone’s gonna steal your equipment”. In my case that is not very likely, this is a very isolated little town, maybe in a different area… and I don’t mind the risk in exchange for total convenience. It’s plug and play.
When there are stronger winds I place tighter ropes and that’s all. This way you might consider a 12 inch newtonian which would be impossible otherwise.

Hey Alvaro,

thx for your answer.
my mount stays out covered in a similar way as yours, my scope comes in once there are a bunch of bad weather days.
My garden is very private as well and i don’t really fear that my gear gets stolen, i mean who could steal a 12 inch anyway
I am not sure if a quality scope would be fine with the following, maybe it would be no problem, but my gear is very exposed to wind and we have multiple days/nights a year where the wind reaches upwards of 100km/h.
my mount does not care but would a 12 inch newton?

Hmm, I don’t know what would happen with those winds… Here last month we’ve had strong winds some days but peak was 78 km/h. The bigger scope (RC12) did move in terms of RA axis movement, I found it next day tilted about 45 degrees with regards to the home park position. But that is no big deal since it is counterweighted, so there is no risk for it to “fall”. It’s like the clutches don’t stop the wind from moving the OTA completely, but it is a slow steady thing that happens in the course of several hours, not one sudden, abrupt movement. In my case it is not dangerous for the setup. Maybe, since a Newtonian is longer, there is a larger lever arm which could help the wind move it faster.

Helpful

andrea tasselli

Frequent contributor

Dec 15, 2024

Anderl:
Tbh i am having quite a hard time understanding the following but, as long as i don’t move the newton within its rings the usage of an electronic rotator and plate solving every night and after every flip should perfectly align the spikes every time? Am i right? I am not sure
A single set of lights for multiple imaging sessions should work in regards to dust and spikes but i am honestly have never thought about an maybe uneven illumination or differing collimation? Over the course of multiple nights to multiple weeks or even months.
is it really necessary to redo flats every night and orientation for every filter using newtonians?

Unless cone error is absolutely ZERO flipping will results in the spikes not being aligned, which might be an issue, especially when the primary isn't masked. And in newtonians the rotational symmetry of refractors is, in practice, lost and not just because of flats. And, yes, you might need to do it time and again, depending on circumstances. Doing that for 2 set-ups is really a handful, to underplay it a bit.

Tobiasz

Dec 15, 2024

Anderl:
thx. This brings me to my concern number 2. is cmos binning that effective that my f10 becomes f5 or do i lose signal somehwere?
oag would be no issue with the edge setup, and my tuned eq6r pro should also be up to the task. At least i would think so.

*
You dont lose signal, only resolution. Binning does not decrease or increase your f/ratio, your f/10 scope is still f/10.

IMO using only f/ratio as a indicator for speed in astrophotography is misleading, because it ignores other parameters. I would check my desired focal length, sensor size und FoV. Then I try to buy the biggest aperture telescope which is available for this FoV and what my mount can handle.

Helpful Insightful Concise

Anderl

Topic starter

Dec 15, 2024

andrea tasselli:
Anderl:
Tbh i am having quite a hard time understanding the following but, as long as i don’t move the newton within its rings the usage of an electronic rotator and plate solving every night and after every flip should perfectly align the spikes every time? Am i right? I am not sure
A single set of lights for multiple imaging sessions should work in regards to dust and spikes but i am honestly have never thought about an maybe uneven illumination or differing collimation? Over the course of multiple nights to multiple weeks or even months.
is it really necessary to redo flats every night and orientation for every filter using newtonians?

Unless cone error is absolutely ZERO flipping will results in the spikes not being aligned, which might be an issue, especially when the primary isn't masked. And in newtonians the rotational symmetry of refractors is, in practice, lost and not just because of flats. And, yes, you might need to do it time and again, depending on circumstances. Doing that for 2 set-ups is really a handful, to underplay it a bit.

Thats cumbersome. I think getting good spikes would still be easy, i could remove the stars from the stack and only use them from the data of one single night/one single flip side.
Speaking of rotational symmetry, is there more to it than just field illumination and spike alignment?
how do other guys manage that problem? There are for sure a lot of reflector scopes sitting at remote sites unable to do flats that often.
if i remember right i have seen some of the remote sites offering something like an once a month flatpannel service.

Anderl

Topic starter

Dec 15, 2024

Tobiasz:
Anderl:
thx. This brings me to my concern number 2. is cmos binning that effective that my f10 becomes f5 or do i lose signal somehwere?
oag would be no issue with the edge setup, and my tuned eq6r pro should also be up to the task. At least i would think so.

*
You dont lose signal, only resolution. Binning does not decrease or increase your f/ratio, your f/10 scope is still f/10.

IMO using only f/ratio as a indicator for speed in astrophotography is misleading, because it ignores other parameters. I would check my desired focal length, sensor size und FoV. Then I try to buy the biggest aperture telescope which is available for this FoV and what my mount can handle.

Some things within this hobby are really hard to get right.

Let me ask differently.
Looking at a picture of an unbinned edge 9.25 imx455 combo, an 2xbinned one and a unbinned but later downsampled to the same size pf the 2x binned.
what are the visual differences i am most likely going to see?

Tobiasz

Dec 15, 2024

andrea tasselli:
Tobiasz:
Each pixel in the EdgeHD setup receives about 1.5x times more signal than in the lacerta setup. So I would definetly vote for the EdgeHD setup.

*Not with my calcs, it is more like 34% more than a 8" f/4. But RON is twice. With dark skies and faint targets that is going to matter.

*
How does you calculation look like? Well, it is still more signal.

IMO read noise is negligible with todays CMOS cameras. Toupteks IMX455 mono has 1.5e RN in in LCG mode with gain 251.

This would be swamped by a factor of 10 within 90s in my 21 mag/arcs sky and luminance filter. 3 times so long with RGB. Todays middle end mounts in combination with autoguiding should be capable of this exposure time per sub.

andrea tasselli

Frequent contributor

Dec 15, 2024

Anderl:
Thats cumbersome. I think getting good spikes would still be easy, i could remove the stars from the stack and only use them from the data of one single night/one single flip side.
Speaking of rotational symmetry, is there more to it than just field illumination and spike alignment?
how do other guys manage that problem? There are for sure a lot of reflector scopes sitting at remote sites unable to do flats that often.
if i remember right i have seen some of the remote sites offering something like an once a month flatpannel service.

*As I said previously it all depends on circumstances. with very bright stars the spikes extend well beyond the reach of SN++ and SXT so those stay. Not masked primaries means that clips diffraction, for bright stars, extends as a diffuse haloes which might not removed in their entirety by SXT (forget SN++), especially shooting RGB with OSC (not your case here).

All other reflectors apart from newtonians ( let's leave coude focus for the moment being) are rotationally symmetric so really newts are a special case. Very large secondaries tend to mask the issue to a degree but then you would loose aperture and contrast and more susceptible to seeing (unless you go real big, in which case it hardly matters anymore). Very few remote observatories offer newts and I have used them all and none has a rotator (well actually this is true regardless whether it was newt or something else...).

Anderl

Topic starter

Dec 15, 2024

andrea tasselli:
Anderl:
Thats cumbersome. I think getting good spikes would still be easy, i could remove the stars from the stack and only use them from the data of one single night/one single flip side.
Speaking of rotational symmetry, is there more to it than just field illumination and spike alignment?
how do other guys manage that problem? There are for sure a lot of reflector scopes sitting at remote sites unable to do flats that often.
if i remember right i have seen some of the remote sites offering something like an once a month flatpannel service.

*As I said previously it all depends on circumstances. with very bright stars the spikes extend well beyond the reach of SN++ and SXT so those stay. Not masked primaries means that clips diffraction, for bright stars, extends as a diffuse haloes which might not removed in their entirety by SXT (forget SN++), especially shooting RGB with OSC (not your case here).

All other reflectors apart from newtonians ( let's leave coude focus for the moment being) are rotationally symmetric so really newts are a special case. Very large secondaries tend to mask the issue to a degree but then you would loose aperture and contrast and more susceptible to seeing (unless you go real big, in which case it hardly matters anymore). Very few remote observatories offer newts and I have used them all and none has a rotator (well actually this is true regardless whether it was newt or something else...).

Am i right if i simply assume that this has to do with the offset and the way the secondary is placed?
really astonishing that people are able to manage newtonians for ap.
how big are the rotational differences? Given that i had a newton that does not lose collimation and i make a set of flats for every like 10 degrees of rotation, any chance that could work?

i can only advise you to try out rotators, just great that i can go to sleep and shoot different targets night over night knowing that my rotator will give me the exact fov i want.

andrea tasselli

Frequent contributor

Dec 15, 2024

Anderl:
Am i right if i simply assume that this has to do with the offset and the way the secondary is placed?
really astonishing that people are able to manage newtonians for ap.
how big are the rotational differences? Given that i had a newton that does not lose collimation and i make a set of flats for every like 10 degrees of rotation, any chance that could work?

*That's in essence correct although in practice real hardware, notably collimation-correlated issues, add to that. I guess if you were to do an extensive flat survey every 10-15 degrees and you keep your imagining train pristine then yes, you could get away from the need to do it recurrently. With DSLRs I had to do it for each imaging session and that adds to the burden, especially on long nights...

Anderl

Topic starter

Dec 15, 2024

andrea tasselli:
Anderl:
Am i right if i simply assume that this has to do with the offset and the way the secondary is placed?
really astonishing that people are able to manage newtonians for ap.
how big are the rotational differences? Given that i had a newton that does not lose collimation and i make a set of flats for every like 10 degrees of rotation, any chance that could work?

*That's in essence correct although in practice real hardware, notably collimation-correlated issues, add to that. I guess if you were to do an extensive flat survey every 10-15 degrees and you keep your imagining train pristine then yes, you could get away from the need to do it recurrently. With DSLRs I had to do it for each imaging session and that adds to the burden, especially on long nights...

Thank you for taking the time andrea.
thats an huge plus for the edge hd setup for me.
really makes me overthink going to get an imaging newtonian. Quite astonishing that i basically never thought about the rotational symmetry as an potential problem, why are people don’t talk more about that?

andrea tasselli

Frequent contributor

Dec 15, 2024

Anderl:
really makes me overthink going to get an imaging newtonian. Quite astonishing that i basically never thought about the rotational symmetry as an potential problem, why are people don’t talk more about that?

If they have rotators and automated flat panels then this is just a minor issue. In fact you may just do it once for each target having a different framing w.r.t the baseline. I myself may redo flats every few months.

Bill McLaughlin

Dec 15, 2024 · Edited: Dec 15, 2024

Anderl:
However, I definitely want a scope combination that allows me to capture quality data more quickly.

Something not often discussed in this regard is backyard non-permanent scopes vs. backyard observatory. If you can swing it, the latter will increase your productivity and consistency and decrease your problems and frustrations. That will make as big a difference in productivity as anything. I speak from personal experience both with backyard and remote.

Well Written Insightful Respectful

Anderl

Topic starter

Dec 15, 2024

Bill McLaughlin:
Anderl:
However, I definitely want a scope combination that allows me to capture quality data more quickly.

Something not often discussed in this regard is backyard non-permanent scopes vs. backyard observatory. If you can swing it, the latter will increase your productivity and consistency and decrease your problems and frustrations. That will make as big a difference in productivity as anything. I speak from personal experience both with backyard and remote.

hey Bill,

sadly not an option. I am only renting the property and can not build an observatory. I already planed for it but things went differently.
thats the main reason, I want to an eq6 class scope. it must be light enough to carry around. it can stay outside for prolonged periods if weather allows but I will take it in if I am on vacation or we have heavy storms, heavy rain/snowfall etc.

cs
andi

what setup would you get?