geordie85

I'm not sure about the Antlia brand but with my astrodon filters they will fit, but I have to turn the faceplate round. Still works perfectly fine.

It's always nice when things finally start working like they're supposed to. 

14 minutes ago, rickwayne said:

Sorry man.

Don't be. You didn't do it haha.

To be fair before I started I swapped my camera from my samyang to my scope. I should have given it a clean before hand.

I've now taken the whole thing apart, cleaned the sensor window, filters, flattener and lens. I'll run some new flats when I've got the time and hopefully there'll be no moving dust bunny. I assume it was moving since flats wouldn't take care of it.

It's just a shame I've lost so much data.

Once again thanks for all the advice.

23 minutes ago, Astropedro said:

I've just ordered an m48 to t2 adaptor from harisons.   Hopefully get it Thursday.   If I've got clear skies tomorrow I'll try imaging with the 51mm (2 × 15.5mm adaptors and 20mm filterwheel) between camera and flattener and see what happens.

Thanks Elp for your insights and thankyou geordie 85 and Steve too.

 

I hope this problem goes away soon  after chatting with you guys. 😊

You're welcome. Hopefully all will work out well for you.

Just making sure I'm clear, my 50mm is from camera body to flattener, not camera sensor. Don't want you having more troubles because of me being unclear.

9 hours ago, rickwayne said:

If I look reeealy closely I can see a much fainter big circle on the flat corresponding to the lower-right problem. So perhaps not an orientation issue after all.

You could run the numbers on the diameters of the circles to see how far the offending thing is from the sensor. I mean, if you find a chunk on the corresponding surface you've only fixed a symptom, but knowing where it's coming from could be instructive. 

Thanks.

It seems that no matter what, my data cannot be calibrated with the flats I'm taking so I'm going to cut my losses and disassemble the entire rig, give it a good cleaning and hope for some more clear nights again soon.

Thanks all for the advice and suggestions.

Not sure if this will help but as I use the same camera and filter wheel I thought I'd try and offer a possible solution.

From the end of the flattener to the camera body I have around 50mm distance and my stars are nice. My imaging train goes scope, flattener, M48 to t2 adapter, 21mm spacer, filter wheel, camera.

What distance do you have from camera to flattener?  From the image you've posted I wouldn't say your stars are out of focus, just alot of coma.

10 minutes ago, Shibby said:

I really don't know - it's always incredibly difficult to figure these things out. But there could be some sort of reflected, stray light, that at some point has passed (possibly backwards) through a filter causing the dark circle. That stray light could easily come from the light panel if it was at night.

That it is. I'm usually pretty good at figuring these problems out but this time I'm beat. Hence asking the collective here.

Strange thing is on my last night I took flats at the beginning and at the end of my imaging session and the data collected that night has the same issue. So it cannot be a moving dust bunny

1 hour ago, Shibby said:

The larger circles don't really look like dust bunnies to me - they might be something related to the filters... The flats don't look quite right. Is it possible that light is leaking in somewhere? Were the flats taken in daytime? Do you have the imaging train covered up?

Flats were taken both at night and during the day.  If memory serves right the above flat was taken at night, but I'm not 100% sure. I'll upload one I know I took at night when I get home. What sort of filter issue could cause this?

3 minutes ago, david_taurus83 said:

Have you got Pixinsight? You could Blink through all the light frames and see if the circles stay in the same place. 

Unfortunately no I don't. I have flicked through them all in DSS though and it appears to be in the same place in all my subs. 

2 hours ago, david_taurus83 said:

The big one looks like it's in an inverted position on the calibrated light stack. If it's bottom right on the flat, it also looks like it's top left on the stack. I would inspect all your lights and see if something has been flipped around or inverted for whatever reason.

The stacked image is 196 lights taken over 2 nights. It's the same even if I just stack 1 nights worth of data.

38 minutes ago, rickwayne said:

I  use bias, not flat darks, with my 183. And with my LED tracing panel I wind up with sub-second exposures even at gain 53. Maybe they're too short but eh, it's good enough for me (check my Astrobin if you wonder if that's good enough for you. Not bragging -- just calibrating).

I agree that it doesn't sound as if there's something wrong with your method. I'd be suspicious of the processing.  Some notions I'd have to run down the problem:

• What exactly is the problem you're seeing when you process with these flats?
• Is the problem something you can examine by stretching a flat sub-exposure, or the integrated master flat?
• Do you have any of your old flats still lying around?  Do they look similar when stretched? Other than the dust bunnies being all wrong, what happens if you swap them into  your processing?

My main problem is there is 1 massive dust bunny that always over corrects and the background is horrible. I've not got round to processing as i don't see the point if my flats aren't working correctly. After stacking Astroart shows an auto stretched image and its always there.

I've also just stacked in Astro Pixel Processor and still getting the same thing. 

Here is an auto stretch from Astro Pixel Processor so you can see what i mean (i'm not bothered about the edge difference as i would crop beore any proper processing). Saved at JPEG at 100% quality for here. Also attached is a single flat frame

25 minutes ago, Stuart1971 said:

Hmmm, it seems that you are doing it all correctly, the only thing I can add, is that CMOS cameras seem to work better with slightly longer flats, mine are all 4 seconds, and 25,000 ADU…

Exactly, that's why I'm stumped. I've never had a problem before, even with short exposures.

1 minute ago, Same old newbie alert said:

Can you post a eg of your flats?

 

I will do in a couple of hours when I'm home

Since this lovely clear spell has ended I finally ran some new flats, but the problem is they're over correcting and I've tried everything I can think of.

I took them exactly the same way as I have always done but this time they're not working, so I have alot of data I can't use.

I use a zwo 183mm, astrodon LRGB gen 2 filters, Esprit 100 with matching flattener and a dimmable tracing pad and white paper.

So far I've tried ADU 30000 taken at 0.5 seconds, 1.17 seconds and 2.5 seconds with a 5 second delay between subs.

ADU 22000 0.5 and 1.4 seconds again with a 5 second delay and all are temperature matched to my lights.

I've tried using different amounts between 30 and 100. All with matching dark flats and the correct darks for my lights. Tried stacking in astroart 7 and in DSS. Also tried average and sigma in astroart.

I set my scope up and left it out in the same place the entire time I was imaging and covered up during the daytime.

I'm stumped and don't want to throw away so much data.

Any more ideas anyone?

Very nice for the small amount of subs 

I've been collecting data on this the past couple of nights myself but like you, my skies haven't been great

The boxing monkey

(Just a screenshot from my phone)

2 hours ago, Steve Reed said:

I would like to keep my newly acquired Skywatcher Explorer 200P primed and ready for action. It will be stored in a dry garage and I seek a suitable cover to keep the dust off. I gather specialist telescope covers are available but was hoping for something a bit more budgety. Thinking of a BBQ or patio heater cover or something similar. Has anyone bought something similar for this setup?

Thanks in advance.

Steve

 

I use an extra large waterproof BBQ cover I got off Amazon for a few £££s

I'm assuming that you didn't dither?

A successful first light is always pleasing. I'd say by the looks of your stars you've fallen victim to some thin clouds.

Check your subs and see if you have any without, the end result will be much better.

10 minutes ago, themcfallguy said:

remove the 11mm spacer?

Yeah that's what I did. Although I am using the 183mm

Try taking out the additional spacer. Personally I don't believe that it's as little as 6.5mm from the sensor to the front of the camera. My reason for this is because I had everything exact and couldn't reach focus. I used a shorter spacer then I got perfect focus without any problems.

The easiest way to do it is arrive before dark which will also make setting up easier.

Also unless there is an actual star party happening, most places won't even have anyone there. I've been to a few very nice places that have been completely empty the entire time I was there.

What a fantastic image, lots of fine detail too. You should be proud of that

Looks a tad green but otherwise a nice image

It connects to the handset straight to your laptop/ pc

I use this to guide my ldx75 

https://www.amazon.co.uk/Meade-Telescope-CP2102-Adapter-Control-Black/dp/B07DFF1LNL?pd_rd_w=NIqfj&pf_rd_p=10d08d47-a6c4-482e-85a7-23115aa14aba&pf_rd_r=J2R9WW8NC3XGV1NDNNCK&pd_rd_r=73f17f5e-b844-450e-9554-eac06181ba17&pd_rd_wg=jmGbQ&pd_rd_i=B07DFF1LNL&psc=1&ref_=pd_bap_m_rp_9_sc

Space isn't black, that's where almost every newbie makes a mistake. You're clipping the data which means that you're basically deleting data.

Look at other images and you'll see that the "blackness of space" is actually more like a dark grey.

Search these forums for data clipping or background clipping and you'll find a much better explanation and advice