Contemplating a Carbonstar 150

Astrophotgraphy isn't hard at all, if your skies aren't crap. I can only answer the first question as far as a 6" newton CT goes: maybe once over the entire night with a 10 degrees drop (that's C not F!). I can't see any difference with a metal tube for a delta of 3 degrees C. My "refractors" (read telephoto lens) are far more sensitive to temperature shifts than that.

I think the use of carbon fiber is a bit of overkill in a 6" scope. I have a 6" f/6 steel tube Newt and I really don't have any issues with focus drift through a night's imaging. If I need to refocus it's usually because of changes in the seeing more than an expanding tube length. Everything of course is more sensitive at F 3.8 but the tube is shorter too. Refractors and SCTs are effected more by temp. changes.

On collimation, if the secondary and primary mirror cells are well designed, I wouldn't worry about collimation changing during a imaging session. In fact, if the OTA isn't transported and protected from large temp. shifts during the day, I would expect that collimation would hold pretty well.

Lastly, IMO you don't need an OAG and I'd avoid the Duo, just use a separate guide scope, it's an easier solution and if its a nicer refractor, you can image with that too.

Hi Phill its me Lena, just get it man, the only complaint I have is that they don't have a bigger 8'' version .

Oh wow I was unaware that they were selling a dew shield for this telescope now, that is a new addition since my purchase. 

Your right its way too expensive I'm never going to buy that, since I could just 3D print an adapter and glue a circular piece of fabric on the front for 20 dollars and it would serve the same purpose. Though I have not had any problems with dew on the secondary in my time so I haven't found the need for that yet, but its still something to consider.

I use a touptek OAG which i made work with my 3D Printed filter drawer by adding some screw holes, I was able to get it a few months ago on AliExpress for like 100 dollars before they stopped shipping to the US. It works great for me, I prefer to off axis guide as it makes up for alot more of my mounts inaccuracies than having a secondary scope. 
The equivalent now would be like a Zwo oag or ogma oag. I think just regular guide scope guiding would work just as well for with that fancy mount.

I hope that helps

Hi Phil, 

I've been using the Carbonstar150 since middle of 2024.  Here's what I've observed since then:

1) Temperature stability has been very acceptable.  All of last year I had been using the ASIAir and did not see a difference when autofocusing on 1 vs 2 C temp changes with the EAF.  I did not try larger temp deltas.  The main thing I saw was that was needing a longer cooldown time in the winter to get to ambient.  During the Summer 30mins was plenty while Winter 60mins was needed.  The extra weight savings of the Carbon Fiber is also appreciated.

2)  Haven't used the Parcor, but it is on my list of things to get.

3) I have been working with the Starizona Nexus 0.75x corrector as my current project.  The corrector does a good job with this scope of correcting out to the corners when everything is Tilt-free and Backfocus is dialed in...  To make this happen, I've been heavily leaning on OCAL 3.0 Max collimator for the telescope end and the Astro Precision Later Tilt adjuster for the imaging train.  As an additional note, the factory Crayford focuser with compression ring clamping around the corrector body is a tilt factory and tilt was noticeable at F4, even more so at F3.  I replaced the focuser with a TS R&P focuser and have been using a screw-in connection for the corrector-telescope attachment.  However, with the mirrors collimated and the imaging train square, I was still getting tilt when screwing them together.  Tape around the Nexus corrector body to allow for a snug fit inside the focuser body removed the sag and resolved that issue.  I think F3 is definitely doable, but a project to get dialed-in.  The main helper has been the Astro Precision tilt adjuster.  Everything you change introduces tilt and I couldn't imagine tying to correct for that in the dark with the limited clear skies I have.  BlurXterminator is also your friend

Here is my recent first light with the Nexus 0.75x:
https://app.astrobin.com/u/J.W.P?i=r72xrj

4) Collimation has been very stable and a non-issue.  The secondary spider is very robust, almost overly so.  The OCAL collimator make adjusting the secondary very easy as you get a live view of what is happening.  The secondary spider does however produce a low incidence internal reflections, which I have since resolved with gaffers tape.  I have an original primary cell cover, which was much better than the replacement injection molded part they had sent me (i.e. no fallout issues with the original 3D-printed cover as the temps drop).

5)  I've been happy with the 2600MC Duo.  There is plenty of light hitting the guide chip with both the 0.95x Apertura and 0.75x Nexus correctors.  No issues with finding guide stars at F4 or F3 with the narrow band filters I've been using (6-9nm FWHM band passes).

Let me know if that helps!
-Jeff

Wondering if Lena or others might chime in here on this–will a 2600 Duo/Air work on the 150CS?  I think it needs a FF-size imaging circle or thereabouts to illuminate the guiding chip.

I have a friends who's offering up a 2600 Duo at a good price and it.  is.  tempting. me to upgrade from my 533MC-Pro – IF it'll properly illuminate the guiding chip.

Clear Skies,
Phil

Hi Phil,

Yes, it will work. 

Re-pasted from my earlier post

5)  I've been happy with the 2600MC Duo.  There is plenty of light hitting the guide chip with both the 0.95x Apertura and 0.75x Nexus correctors.  No issues with finding guide stars at F4 or F3 with the narrow band filters I've been using (6-9nm FWHM band passes).

Jefferson:
Hi Phil,

Yes, it will work. 

Re-pasted from my earlier post

5)  I've been happy with the 2600MC Duo.  There is plenty of light hitting the guide chip with both the 0.95x Apertura and 0.75x Nexus correctors.  No issues with finding guide stars at F4 or F3 with the narrow band filters I've been using (6-9nm FWHM band passes).

I have the 2600MM Duo on an f3.8 refractor with 3nm filters and I have found it unreliable finding guide stars. Maybe a less restrictive band pass would be better? I've been tempted to swap it out for another FW I have with less restrictive filters.

Which refractor, if you don't mind me asking?

Clear Skies,
Phil

Another question entered the bear brain as I stumbled through the forest of life:

I currently have an NP101 with a 540mm focal length at f/5.4 and an unobstructed 101.6mm of aperture.  So between the NP101 and CS150 it's a meaningless difference in pixel resolution.

My question would be SNR, and it's not as cut-and-dried as I initially drew it up in my head.  The CS150 has a 570mm focal length with the coma corrector at f/3.8.  At first glance this would mean (5.4/3.8)^2 or a 2.02X boost in imaging speed.

The effective aperture is ~135mm.  I calculated that first as (150^2 - 62^2)^0.5 to account for the 62mm secondary for 136.6mm aperture than clipped a tiny bit more off to account for the spider vanes.  So with the 0.95X coma corrector I get 570mm at an effective f/4.22.  Still really fast for 570mm FL.

So by running these numbers, I'd have about the same focal length as my NP101 but gather light (5.4/4.22)^2, or 1.64X faster...

...or would it STILL be more?  Would the increased aperture of the CS150 vs. the NP101 tack on an additional boost to SNR?

Clear Skies,
Phil