Clarkey

These are a great start. Get your integration times up a bit and your on a winner. 👍

14 minutes ago, Mark - Coventry said:

The internal reflections have me a little stumped in fact as I have flocked all possible surfaces

The internal reflections are between the sensor and filters or CC, so flocking does not help. It is also possible that you might get similar with a refractor. The other link to my SGL post has a bit more detail. Not easy to fix though.

13 minutes ago, Mark - Coventry said:

1600 microlensing

The 1600 does micro lens at times but this is a smaller localised effect. The large halo around the bright star is caused by internal reflections.

There is a link here with an example of microlensing.

https://www.cloudynights.com/topic/646966-zwo-asi1600mm-pro-bright-star-issue/

40 minutes ago, JamesF said:

explaining it better in the process

I think Vlaiv explains most things better than us mere mortals!

Nice image for 2 hours given the relatively low surface brightness. Triangulum might benefit from a bit of Ha with the l-enhance if you want to add any more data.

At f1.8 in bortle 5 you are likely to find anything over a couple of minutes is likely to swamp the image with background light. Obviously this will depend on the iso setting and any filters. The mount will depend on how good your alignment is and the mount tracking. Although there are various way of calculating these things, my suggestion would be trial and error. Just set a number of exposure lengths to see what works best with your set up. I'm guessing something around the 1 minute mark would probably be good.

Useful to know that you can get spares for the ZWO kit. Did you you get it directly from ZWO or through a 3rd party?

2 hours ago, sharkmelley said:

12mm

Hmmmm. That is probably about right for the sensor to filter distance. If this is the cause I'm not sure how easy it will be to fix. With the f4 scope I already get some vignetting with the 31mm filters and moving it further away will undoubtedly make it worse. I can also try turning the filters round.

Thanks for the help everyone. At least I have something go work with.

On 01/12/2021 at 17:05, Mark - Coventry said:

However I am getting really weird reflections which I'm struggling to track down. 

I have started to get exactly the same problem with my TS Photon and have a thread in the imaging section on the same subject. Suggestion seems to be internal reflections between lenses or filters. I need to look at it when the next clear night happens.

N+1. It's the law.😆

I have two spacers before the filter wheel so I'll put one before and one after to test. If this is the problem it may not be an easy fix on the faster scope. New filters and wheel is not going to get passed the boss!

Just need a clear night to test!

12 minutes ago, inFINNity Deck said:

reflection between the camera and filter.

I will have to do some more investigating. It is a viable possibility - I just need to prove it.

It is a bit odd using similar set up (filters and camera) with a number of different scopes, flatteners and reducers and this is the first time I have seen this. I even imaged the western veil using the same scope and imaging train without issue. I am confident that the filters are the right way round. I was very careful when they were installed.

3 hours ago, sharkmelley said:

It is likely to be a reflection between the camera (sensor or front window) and filter. 

Once I am back home I'll have a pixel count. The overall reflection just looks too big for a reflection of this type? It's nearly 1/3 of the frame.

8 hours ago, Budding Star Gazer said:

That looks like light reverberation from the inside of your OTA, id say check the reflection before & after adding dark material

Should have added - the OTA is fully flocked already.

3 hours ago, Allinthehead said:

That looks great. The only feedback I'd offer is to keep adding more data and you won't need so much noise reduction.

Definitely agree with this sentiment. More data will give a cleaner and more detailed image. Cleaner data is also easier to process.

WRT the gradients, this is really something best dealt with in the software. Obviously there is PI but I use APP which also has very good gradient removal tools. You don't say what you use to process, but the right tools certainly help. (The 'right tool's is another whole debate).

Great image. Keep going and keep posting.

Hi,

I am after some guidance from the collective mind of SGL.

Last night I was imaging in Ha and OIII using the Photon F4 newtonian, aplanatic coma corrector, zwo EFW and filters with a 1600mm pro. I have imaged with this same set up previously without issue, but this time there was a bright star in the field of view. Although I used to the usual problem of halo's round stars with the OIII, this time I had really bad reflections with both the Ha and OIII. In fact the Ha was much worse. For info there was no moon and there are no lights overlooking the scope. Additionally it can be seen on all the subs - not just some. Does anyone have any idea of what might have caused this reflection? Below is the stacked Ha channel.

1 hour ago, Grant93 said:

Whats the difference between the two

The 120mm mini is mono whereas the 120mc is colour. Also being USB 3 you will get a much better frame rates. As Astromuni says you could consider the 224 which is a better planetary camera.

Looks like a rebranded version of FMA 180 which I have. If so, it is designed as a small astrograph and personally I have been pretty impressed with mine. Some people have suggested it suffers from CA, but the example I have seems pretty well colour corrected. I usually use mine with a Canon 600D and it gives a good corrected field to the edge of the frame. Personally, for the price I think it is excellent.

The 120 min and a 50mm guidescope will be fine up to about 800mm FL. You could push this to about 1000mm depending on how fussy you are and how accurate the mount is. You might need an extender to get focus on the guidescope - I'm not sure. Depending on how you are going to control the mount you might need a cable to the mount such as Lynx Astro FTDI EQDIR USB Adapter for Sky-Watcher Mounts (see description for models) | First Light Optics. I would suggest this is a better option than using the ST4 guiding - but that is just my opinion. The only other thing you might want to think about is possibly getting the 120 mc which you could use for planetary imaging with your Dob. It won't be sensitive as the mono, but it is USB 3 and at F4 should still be more than able to guide.

With regards to RPi or mini PC it is really a personal choice. I actually run everything remotely over a 10m USB 3.0 active cable from a laptop or PC in the house. I have considered using a mini PC, but the set up I have works (normally) so I have kept to what I know.

All your choices seem pretty reasonable to me.

5 hours ago, Tim said:

M31 is one of the trickier targets to get "right,"

Agreed. Easy to image but difficult to image well. A bit like M42. These two are nearly always the 'beginner' targets even though they are not easy to get a great result from. The best thing about both is that they can give pleasing results with minimal integration time.

FWIW I recently posted an M31 on the 'Deep Sky' imaging forum which was about 7 hours data. You wouldn't know it looking at yours. Keep going with more integration. You are definitely on the right track.

2 hours ago, Marvin Jenkins said:

Seems clouds are more a part of Astronomy than Astronomy

Is there a study of clouds in the dark? Noctonephology maybe🤣

I have read that you should leave everything in place to take the flats (including the dew shield). However, I always remove the dew shield and rest the screen on the OTA pointing towards the zenith. Never had any issues doing it this way.

23 minutes ago, jjosefsen said:

I really hope I can get this thing working well, as I plan to upgrade it to an 8" version at some point, maybe when I finally get around to building an observatory.

I followed the really good advice from David when I was trying to collimate my RC8. I have developed my own method (albeit very similar to that described by David but using the REEGO (TSRCKOLLI). Follow the guidance carefully and you will get there. It is worth the effort as the RC's are excellent for AP.

Given the full moon earlier in the week I was looking for a bright target to give my little FMA180 a proper 'first light'. M31 taken with a modified Canon 600D, a total of 70x120s, 80x180s and 24x300s giving 6.3 hours overall. Stacked and light pollution removal in APP and processed in Affinity. No noise reduction.

Overall I am quite pleased with this little scope. I had heard that it suffered from significant CA, but from this image it is certainly not too bad. Imaging is at just under 5' per pixel with the Canon. This is likely to be my 'travel' set up but maybe change the HEQ5 for a star tracker.

CC welcome.

Really nice image. Nice and crisp.