Celestron 127 slt

[Simon Pepper]

Hi all

i have been imaging with my redcat for a year now and had some ok success with it I love my rig and what it can do, but now we are in galaxy season some more focal punch is needed for these targets. It suddenly occurred to me I have my first scope the 127 sitting gathering dust from years ago when I first started out visual on planets and moon. Is it possible to use my zwo 294 on this scope and if so how? Where would I attach the camera I assume right on the end without any diagonals? Also is it worth even trying or am I going to be wasting my time due to issues I may encounter and longer focal lengths with shorter F ratios? Interested to know if anyone else has tried this. 
thanks 

 

[Nik271]

I'm assuming you already have tracking mount that can take the weight of the scope? At 1500mm the focal length is good for galaxies. You will be oversampled a bit, but it should be fine if you guide or use shorter exposures unguided. The camera can be inserted directly into the visual back.

Last summer I managed to image the ring nebula using only 30 sec exposures with a similar scope the Skywatcher Skymax 127, so DSO imaging is doable.

Nik

[Simon Pepper]

Hi Nik,

yep got heq 5 pro so should be good there. Any ideas what kind d of back focus I need?  Will be the same as I have with my redcat? I have guiding as well so should be good Thanks for this though sounds like its worth a shot 👌

[Paul M]

I've used my ASI 178  with my Celestron M127 Mak. I get eggy stars, not the best scope/camera match but it  works.

I connect the camera directly to the back of the stock Celestron adapter as you will maybe make out by zooming in on the image below:

[Nik271]

8 hours ago, Simon Pepper said:

Hi Nik,

yep got heq 5 pro so should be good there. Any ideas what kind d of back focus I need?  Will be the same as I have with my redcat? I have guiding as well so should be good Thanks for this though sounds like its worth a shot 👌

One good thing about Maks and SCT is that back focus is not a problem as you adjust the focus by moving the primary mirror which gives a huge range of focus. 

[Nik271]

So I decided to test my own advice, took out my SW 127 Mak yesterday on EQ5 with RA motor, no guiding. Made 50 subs of 30 seconds each with an unmodded DSLR, of which only half turned out to be usable. The transparency was poor and M51 was only 50 degrees up at 10pm. This is the resulting rescaled stacked image after some minor editing (original crop was 2000x2000 pixels but was too noisy).

 

I dare say with a dedicated astro-camera, better tracking and longer exposures, (maybe 60-120secs) much better results can be obtained.

It's never going to beat a RASA but hey, it's just a small Mak

Edited April 5, 2021 by Nik271

[Simon Pepper]

Pretty good result I have a clear night tonight so will give it a shot thanks 

[Simon Pepper]

I thought I would share this was just two hours with calibration frames. I have never used another scope just my redcat which is 250mm this slt was 1500 so I was thinking it was going to be an uphill task but I was surprised with the result considering it comes in at F12! The focus is a little soft as trying to get that right without bahtinov mask and dedicated camera was hard (I have now ordered a mask). But thanks really for giving me the encouragement else I wouldn’t have bothered! 

[Paul M]

That's an excellent result. 

I get very soft focus with my Mak127 and ASI178 camera.

I don't have many examples from that combo. Not Deep Sky anyway. 

I did use it to image the Nova in Cassiopeia recently.

[Simon Pepper]

Thank you I was really surprised as well didn’t expect this I am bortle 4 so that would have helped had good seeing. That’s a great image as well I have heard about this nova from Alyn  Wallace am I right in saying a nova is a new star? Did you centre on another object or have the coordinates as this could be my next target fascinating to know it’s a brand new star!

[Paul M]

On 06/04/2021 at 17:00, Simon Pepper said:

Did you centre on another object or have the coordinates as this could be my next target fascinating to know it’s a brand new star!

Hi, sorry only just noticed your question!

I just put the RA/DEC into APT and used GOTO and plate solving. I've got it saved as a custom object in APT's object database so it's just a few clicks away.

It's a new star at that brighness but the progenitor was already known and can be seen in pre-nova images that reach deep enough magnitude.