schmaks avatar
Hey there,

I currently shoot with a ZenithStar 73 on a heq5pro but am longing for a deeper focal length…

What do you think is a next good step?

I have been considering the Explorer Scientific 152 or even the edgehd telescopes. I know I’d likely need a new mount for the edgehd, but would love some insight.

The cheaper explorer scientific 152 (white f6.5) should be light enough for my heq5pro but I’m not against upgrading my mount in the name of depth and detail.

I’m open to suggestions!

Thanks!
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Drew Lanphere avatar
Another option you might want to consider would be to get a camera with smaller pixels, which would increase your resolution as well.  The ASI 183 (in color or mono) for example has tiny pixels that would nearly double the resolution from your existing dslr.  And they have good resale value; you wouldn’t have difficulty selling pretty much any cooled Astro cam if you wanted to move on.  You could play around with combinations of scope/camera/target at this website:  https://astronomy.tools/calculators/field_of_view/
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David Redwine avatar
An 8" Edge is a very capable scope.
schmaks avatar
Good to know! I'll look into the potential of upgrading the camera as well! I think one of the smaller edges looks enticing and perhaps would upgrade the camera simultaneously.

Would my ZenithStar 73 suffice as a good guide scope for an edge?
Drew Lanphere avatar
If you're going to use a guide scope, the Zenithstar might be a bit of overkill (and also fairly heavy).  Many (most) will tell you that you should use an OAG with an SCT.  I don't for my Edge 8", guiding with a simple 50mm guide scope, and it works pretty well.  Here's one taken with that setup.  https://www.astrobin.com/x6l6qa/?nc=userOne thing - smaller pixels with a longer focal length scope like the Edge makes guiding and getting round stars MUCH more challenging.  So if I were you and decided I was going to get an Edge, I'd  probably wait on a new camera and stick with your DSLR at first to get the hang of the system.  That's a lot to learn all at once.
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schmaks avatar
Thanks! That makes sense!
David Redwine avatar
If you go with an Edge I  recommend getting the 0.7 focal reducer.

I have my 8" Edge on a CGX-L now along with a Celestron OAG and the Zwo 290 Mini .  I still have the Zwo 120MM on a modified Celestron RACI (increased inward focus travel).  A recent comparison between the OAG and the guide scope showed little difference (1.25 to 0.5 sec. for both).  The OAG was a bit better for a target at a Dec. of -25.  But on Sadir PHD had trouble with calibration of the OAG without turning on "Assume orthogonal R.A. and Dec. "  The OAG was also less reliable (more lost guide stars) due to the fact that with OAG you are often  using a star with significant coma.

If I only had one guidance choice it would be a short stiff refactor of about 180mm f.l.
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schmaks avatar
What camera would you all suggest as a replacement to my DSLR?
schmaks avatar
With the ASI183, does it have a memory card slot or do i need to hook it up to a computer or the asi controller?

i am considering the asi guide system so am curious how that all works.

Thanks!
Drew Lanphere avatar
The 183 needs a computer or asair-type hook up.  There are a bunch of new CMOS cameras with which I’m less familiar.  I’d try to read a bunch of reviews on forums like this, etc.
schmaks avatar
Will do!

i am looking into the asiair guide system… it’s be nice if that could also record images from the main camera but I don’t believe that’s the case.
David Redwine avatar
For a complete description of the Asiair pro's capability see:

https://astronomy-imaging-camera.com/product/asiair-pro
Bruce Donzanti avatar
I  have a C11"EdgeHD with a Stellarvue 80mm APO triplet piggybacked on an AP1100  in my observatory.  I also have an Esprit 120mm APO triplet.  They all have pros and cons.   The Stellarvue is an excellent refractor and a step up over the Skywatcher Esprit but I think the Esprit is very good.  Adding it on a good mount and you are off and running.   I use an OAG on the C11 like David mentioned and it works well but can be finicky at times.   The large SCTs like the C11 and C14 have a lot of flexure so I am not sure even a sturdy guide scope would be better but some do use them, especially when they use the hyperstar lens for f/2.

As far as cameras, I am using the ASI533 and ASI2600 OSC and ASI1600 mono.  All excellent CMOS cameras.  These have larger pixels than the 183 that Drew mentioned but the 533 and 2600 have very low noise and no amp glow.

I haven't tried the askari guide system  but out looks interesting.
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schmaks avatar
I don't think it'll be long before I have a guide scope/system (ASIAIR PRO) and a new camera… looking forward to the results! Reading about the plate solving and auto-stacking previews continues to sell me on this being the next step. Thanks, everyone, for the input.
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Ian Dixon avatar
Great thread, thanks to the OP and those contributing…
schmaks avatar
I agree—I've come a long way in the short couple of months since I began this hobby—all thanks to the helpful responses I get on here (even if I may ask too many questions at times).
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Ruediger avatar
Hi Schmaks,

A (bigger) SCT is not easy to handle. You always have more or less mirror movements. Especially after Meridian flip or slews. An OAG is mandatory. Using a guiding scope is tedious. I have tried that for years with my Meade LX200 12" - finally I gave up and used an OAG and everything improved dramatically.

Moreover you need a quite good mount otherwise you will fight with 2 problems: Mirror flops and tracking/guiding. Also you have to re-focus frequently due to mirror shift, so a motor focus is a reasonable add-on to automatize it or run it unattended.
Going for a big SCT is very challenging.
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schmaks avatar
Good to know!

Something like the WO Fluorostar 132 as a next telescope might be a good option for me—but I think I will first upgrade to a guided system and a new imaging camera first, as much as I'd like a larger focal length sooner than later. In time.
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Ruediger avatar
It is never a mistake / failure to invest into a bigger refractor. Easy to handle and very reliable. SCTs are sometimes very bitchy and can wreck your nerves. If you go for galaxies then a larger Newtonian is also a good choice.
If you are really seriously thriving for long focal length (without excessive frustration potential) then you need an excellent mount and to consider RCs oder CDKs. But this is a completely different level of invest.
David Redwine avatar
Mirror lock on the Edge prevents mirror flop.
Rich Sky avatar
How about a Planewave24 Ritchey-Chretien astrograph f6.5? . I asked Santa for one.
Ruediger avatar
David Redwine:
Mirror lock on the Edge prevents mirror flop.

Hi David,
I know quite a lot of people who have trouble even with the lock. Even Celestron proveds some data for a remaining play of the mirror.
There will be always minor moves in any moveable mirror.
Ruediger avatar
Rich Sky:
How about a Planewave24 Ritchey-Chretien astrograph f6.5? . I asked Santa for one.

You definitely asked Santa for an amazingly beautiful instrument.
philhilo avatar
Hi Schmaks,
A long tale, so feel free to cut to the last paragraph.

I cant advise on the choice of OTA but I have been pondering upgrades after a couple of years from starting to take pictures through an 8inch Newt to where I am now, a fairly well automated system still using the Newt and but a modded DSLR. On the way I aquired a WO66 refractor, and ASIAir (I gave up on this and it lingers in a cupboard) and it all sits on an HEQ5 Pro. I live under Bortle 8 skies so I need a lot of integration time. And hands up I like galaxies, so I need reach. I have a set up I can polar align using Sharpcap in 2 minutes and then go and sit on the sofa in the house, program in a sequence of exposures and targets for the night and go to bed. I get up in the morning and its all very neatly parked. Sounds neat, however every step of the way has been a mission, so many nights of nothing, months of scratching my head, seeking out answers from the community, and general pulling hair out. Then we get to processing, don't mention processing! Where to go from here? Camera, mount, OTA, software? My setup is right on the weight limit for the mount, and I should upgrade, but on the whole I get good guiding (as long as there isn't a breeze, but I am usually tucked away from the prevailing winds). So that can wait. A new OTA? To get the reach and aperture is going to set me back £2000 for a second hand OTA and flattener. Software - I don't have the time at a good time of the day (job and a 2 year old to look after) to try to understand Pixinsight so I use Startools and am just starting to get results, but that has sent me back to my rig to understand where a myriad of issues thrown up by the better processing. However I need a few more months to get comfortable. So how do I get bang for buck? First up improve my current OTA to the best it can be, £400 or so (change the focuser, flock the interior, etc, etc) so that it is delivering the best possible image. Then for the next step a mono astrocam is going to make the biggest difference at around £1-1.5k. Lots to learn but at least I know what the rest of my kit does - even better would be a colour astrocam, get that integrated, understand that and how it effects the set up. Then move to mono (probably loose nothing on the OSC assuming I get it 2nd hand). Get that sorted. Then upgrade the mount, to an EQ6 R Pro, that will carry anything I can ever likely afford, then when I am flush go for the long fl triplet. All that is probably a 2 year plan for the first two steps, then whenever for third step.

So a long story, but slow steady steps so you have some idea as to what is working, and what needs fixing, but the idea of changing everything all at one go looks like a brave step, and is going to need a lot of patience (even more than the normal astrophotography head banging experience!).
Whatever, enjoy your deliveries and clear skies!
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