WO GT71 suddenly died - new scope with GEM45 -> Galaxies?

[drivera]

Hey,

I tried to quickly surmise my situation in the topic!

So in the UK it's been terrible weather for months and with limited time (can't image during the week) it was about 2 1/2 months since I have tried to image. I have a GT71 setup with a ZWO 533MC, on my GEM45 (don't get me started but won't be upgrading soon).

I went to image about 3 weeks ago on my first calendar cleared/clear skies and I suddenly couldn't get focus, even more, the stars were off and my mask couldn't pull any spikes. I always take my scope and gear all off, don't touch it, store it and return it for my next session. Something has gone wrong and maybe suddenly knocked (wife wants to blame a cleaner, and I want to blame the wife so we resulted in natural causes and force majure).  I'm doing first tests on it on my next clear night such as removing the flatenner to see if it is that or not. Otherwise, something has damaged the scope and it seems FLO are manic busy can't do any tests, and I will see if Rother Valley can do a check. It's also out of warranty.  

So...back to my main next question. I'm going to have to buy a new scope. I've loved the GT71 for widefield and it's beautiful but I would love to get into galaxies more. I have been trying but unsuccessfully identifying the right scope like a RC8/10 that would provide great images for galaxies, but under acceptable GEM45 weight (45lb/20kg).

I'll be imaging with my 533MC until in the next 4-6 months I'll step up to mono (not sure which camera).

What scope would you go for to image galaxies but can handle the weight on GEM45.

Thanks!
 

[Clarkey]

You haven't given a budget, but I will give my opinion anyway.

I have an RC8 and in terms of value for money it is excellent. Once collimated (which some find difficult) it is an excellent scope but most require a focuser upgrade. Personally I am a fan of the Baader Steeltracks.

I also image with a 115mm refractor, which gives very similar results to the RC, although slightly slower optically once the RC8 is binned.

I am also considering a fast Newtonian due to the limited imaging time. I am looking at a 10" version to give a good FL even if I decide to use a Nexus 0.75 reducer.

Typically, I image at 1 to 1.5 arc secs/px which I can do with the above. At the end of day, it depends on how deep you pockets are!

Obviously, you can spend more and go bigger but it would be pushing your mount.

[drivera]

Ah yes thank you!

My budget ideally would be < £2k, but also thought given the mounts weight the scope wouldn't extend / push past that anyway? But could assume wrong?

[CCD-Freak]

I have used an RC6 and C8 OTAs on my GEM 45 for galaxy imaging.  The RC10 scopes are just too large and heavy for the GEM45.

Pictured is an RC6 with an AP67 reducer at F7 on a GEM45 and an image of NGC253 made with the pictured scope and a ZWO ASI482MC non cooled planet cam.

The other scope pictured is a Celestron C8 classic ribbed back OTA. 

Edited February 14 by CCD-Freak

[Elp]

Which galaxies, the majority are tiny...

[M40]

Just going to throw a couple out there, the skywatcher 200mm quattro and the stellamira 125. Both give a similar fov but the quattro is an f4 light bucket and the sm125 is an f7.8 lightweight instrument. I've seen what has been achieved in the eeva forum with the quattro and I have just scratched the surface with the sm125 but I have high hopes for it. Significant difference in weight between the two which should also be considered. 

[Stuart1971]

2 hours ago, drivera said:

Hey,

I tried to quickly surmise my situation in the topic!

So in the UK it's been terrible weather for months and with limited time (can't image during the week) it was about 2 1/2 months since I have tried to image. I have a GT71 setup with a ZWO 533MC, on my GEM45 (don't get me started but won't be upgrading soon).

I went to image about 3 weeks ago on my first calendar cleared/clear skies and I suddenly couldn't get focus, even more, the stars were off and my mask couldn't pull any spikes. I always take my scope and gear all off, don't touch it, store it and return it for my next session. Something has gone wrong and maybe suddenly knocked (wife wants to blame a cleaner, and I want to blame the wife so we resulted in natural causes and force majure).  I'm doing first tests on it on my next clear night such as removing the flatenner to see if it is that or not. Otherwise, something has damaged the scope and it seems FLO are manic busy can't do any tests, and I will see if Rother Valley can do a check. It's also out of warranty.  

So...back to my main next question. I'm going to have to buy a new scope. I've loved the GT71 for widefield and it's beautiful but I would love to get into galaxies more. I have been trying but unsuccessfully identifying the right scope like a RC8/10 that would provide great images for galaxies, but under acceptable GEM45 weight (45lb/20kg).

I'll be imaging with my 533MC until in the next 4-6 months I'll step up to mono (not sure which camera).

What scope would you go for to image galaxies but can handle the weight on GEM45.

Thanks!
 

Send it to RVO, they have the kit now to do full Zygo tests, and re align if needed, I don’t   think FLO have any kit like that, and would need to send it out to someone for testing…I have mine done at RVO and they were excellent…👍🏻

[Adam J]

3 hours ago, drivera said:

Hey,

I tried to quickly surmise my situation in the topic!

So in the UK it's been terrible weather for months and with limited time (can't image during the week) it was about 2 1/2 months since I have tried to image. I have a GT71 setup with a ZWO 533MC, on my GEM45 (don't get me started but won't be upgrading soon).

I went to image about 3 weeks ago on my first calendar cleared/clear skies and I suddenly couldn't get focus, even more, the stars were off and my mask couldn't pull any spikes. I always take my scope and gear all off, don't touch it, store it and return it for my next session. Something has gone wrong and maybe suddenly knocked (wife wants to blame a cleaner, and I want to blame the wife so we resulted in natural causes and force majure).  I'm doing first tests on it on my next clear night such as removing the flatenner to see if it is that or not. Otherwise, something has damaged the scope and it seems FLO are manic busy can't do any tests, and I will see if Rother Valley can do a check. It's also out of warranty.  

So...back to my main next question. I'm going to have to buy a new scope. I've loved the GT71 for widefield and it's beautiful but I would love to get into galaxies more. I have been trying but unsuccessfully identifying the right scope like a RC8/10 that would provide great images for galaxies, but under acceptable GEM45 weight (45lb/20kg).

I'll be imaging with my 533MC until in the next 4-6 months I'll step up to mono (not sure which camera).

What scope would you go for to image galaxies but can handle the weight on GEM45.

Thanks!
 

Never heard of anything like that before.....very very odd. My bet is that it's something very simple that you have missed. The GT71 is actually a very simple but of kit you know. Perhaps some pictures and a sub will help people help you. 

[PhilB61]

Can't help with your new telescope choice but I'm with Adam above. It would take a very significant impact to knock things that far out to not be able to focus. If the lens cell is firm and non of the elements are loose (try gently shaking) and the focus tube is secure then it can really only be a spacing issue. I presume you are manually focussing, can the tube move freely over it's whole range. Have you tried with an eyepiece with/ without the flattener to try and narrow down the issue, you may need a diagonal for visual to get the necessary backspacing. Some of this testing could be done in the daytime if you have a distant object to try and focus on.

[drivera]

12 hours ago, Stuart1971 said:

Send it to RVO, they have the kit now to do full Zygo tests, and re align if needed, I don’t   think FLO have any kit like that, and would need to send it out to someone for testing…I have mine done at RVO and they were excellent…👍🏻

Oh amazing thanks for the recommendation.

[drivera]

1 hour ago, PhilB61 said:

Can't help with your new telescope choice but I'm with Adam above. It would take a very significant impact to knock things that far out to not be able to focus. If the lens cell is firm and non of the elements are loose (try gently shaking) and the focus tube is secure then it can really only be a spacing issue. I presume you are manually focussing, can the tube move freely over it's whole range. Have you tried with an eyepiece with/ without the flattener to try and narrow down the issue, you may need a diagonal for visual to get the necessary backspacing. Some of this testing could be done in the daytime if you have a distant object to try and focus on.

Ah didn't think I could do it in the daytime. I'll hook the camera up without the flattener and see if I can focus during the day time, plus check again nothing is loose. It is very weird.

[PadrePeace]

You say you leave all the gear intact when you store it in between imaging sessions. I assume, because you have not been that clear, that the optical path from scope lenses to camera is not broken down at all for storage? If this is not the case then I’d say either something has got inside the optical path and is disrupting it, but as you have offered no images this is pure guess work, or you have left out an adaptor and the back focus is now incorrect. I have the same scope and it has a well engineered focuser and rack pinion mechanism. It’s so simple that inless the gears have stripped stooping the focus set from moving it must be a BF error.
 

Please elaborate with images and a clear indication of how you store the scope with or without the camera or we are all fishing in the dark on your behalf. 

[Sp@ce_d]

Has no one seen the obvious, it’s the old N+1 justification “issue”.. of course you need another scope it’s galaxy season !🤣 … I’ve had this issue with many a guitar when that G string just wouldn’t stay tuned properly 😂👍 it’s amazing how these things tend to fix themselves once you introduce some “sibling” rivalry from another scope added to the collection 😁

[Steve Ward]

It's not something simple such as the focus lock screw being tightened which you've forgotten to loosen ?