IDM

Superb advice. I will make the changes and try again Many thanks, Ian

The standard Celestron Velcro one. Though, I have been wondering if that's part of the problem as I have taken the flats without the dew shield, is that wrong?

Problem occurs with my C8 SCT with f6.3 reducer

Unfortunately, I am seeing vignetting, this doesn't seem to happen with my refractors it is something that has become worse when trying to take Flats with my C8 SCT. Currently Graxpert is doing a good job of sorting it out, but that clearly isn't the best approach!!

That's very helpful, so don't touch the gain just dim the panel with more layers . I am thinking that this is likely to need tp be very dim and therefore even with the light panel on the end of the scope there will need tp be some sort of seal to prevent stray light creeping round the edge, or take the flats in total darkness. Would that be right?

M106 taken using my Celestron C8 with Meade 0.63 reducer and a Zwo ASI 294 MC pro camera. Capture software was NINA with PHD2 for guiding (separate guide scope currently being used). A total of 239 90 second subs taken at bin 2. The subs along with flats, darks and dark flats were stacked with Pixinsight using weighted batch pre processing. All subsequent steps were performed using Pixinsight to get the final image. I am still not sure I have the C8 optimsed properly with the back focus from the Meade reducer. Additionally I have convinced myself that my flats are not right as there was a lot of vignetting and. some rather odd halos concentric to the galaxy. The capture was probably not helped by a rather prominent moon, but if I waited for clear skies and no moon I wouldn’t capture anything! Thanks for looking Ian

I have been using flats for several years but recently was wondering if maybe the flats I was taking might not be as good as they possibly could. My current method is to use a light panel with several sheets of white A4 on top to dim the light source. I then adjust both the gain and the exposure time so that I can achieve an exposure time in the region of 1.5 seconds and the histogram at or around 50%. In order to see if I was doing anything wrong or if my results could be improved I had a look around the web and seemed to find some conflicting information. Some sites state that the camera gain should be the same as used to capture lights. The problem I have with this is that if I keep the gain the same I end up with very short exposure times if I am to keep the histogram at or around 50%. This then conflicts with other online advice that states that flats exposure time should be somewhere in the range of 1-3 seconds. Given I have spent hours optimising and capturing data I don’t want potentially reduce the quality of my processed image through poor calibration. Therefore What do people consider to be the best way to capture flats? Thanks, Ian

I was very excited when I first processed the image as I felt I was making some forward steps and I certainly appreciate all the feedback that will hopefully help me improve still further in the future. Though at times it feels like the more I learn the less I know 🙂 but I think its part of what makes this hobby so fascinating and possibly addictive, as there is always room for experimentation and improvement. Thanks, Ian

Thanks for the positive comments.

Thank you for the kind feedback. I am trying to be more subtle with my images. In planetary my enthusiasm used to get the better of me so I am trying to be cautious to achieve less = more. Ian

@ollypenrice Thank you so much for the comprehensive and really helpful feedback I will have to spend some time digesting and learning. Ian

Thank you for the kind words.

Last year I bought a C11 for planets which had a Celestron dew ring heater and it has been really successful in controlling dew. Indeed I have been using it without a dew shield with no problems. Just the other week I picked up a C8 with an F6.3 flattener/reducer for galaxies. I have only tried it once (I just posted my M51 image in the DSO imaging section). I haven’t sorted all its issues particularly with the reducer but it seems a good scope. I bought my C8 secondhand it was cheap and it’s quite light. cheers Ian

I recently acquired a Celestron C8 XLT with a Meade flattener and this image was taken on its first outing. I am not very confident about the Meade F6.3 reducer/flattener as the back spacing seems difficult and certainly I had very bad vignetting across the image that required a heavy crop prior to back ground extraction. Just to make my life more difficult the night I took the images I also decided to migrate from Sharpcap to Nina. Nina seems excellent but it didn't seem so intuitive as Sharpcap, though it handled the meridian flip with my Zwo AM5 perfectly (I followed Cuiv's settings from Youtube). So in the end I ended up with 217 90 second exposures using the C8 with Meade reducer and a Zwo ASI294 MC pro camera. Guiding was provided by Skywatcher finder-scope I converted to guidescope, focal length 185mm (approx.). It's not the best but I felt for a first outing I was pleased. Processing was done using a newly acquired Pixinsight license, so again I am at the bottom of the learning curve!!! Since taking the image I had a look at the Collimation and with a backspacing of 105mm I noticed good collimation at the centre but put poor round the edges. So I don't things are right. I have since reduced the backspace to about 75mm and the collimation looks better across the sensor. The weather hasn't been great since the change so I haven't been able to test it by imaging properly, though I did do a plate solve and Nina (ASTAP) reported a focal length of 1336mm which seems a little long. I would be grateful for all thoughts on the reducer and helpful feedback on the image

Whilst it will work it’s not great as you will be considerably over sampled. The easy way to check telescopes with different cameras is to use this online calculator: https://astronomy.tools/calculators/ccd_suitability It suggests the combination is not good also the lack of cooling doesn’t help. Though I do know some planetary camera are better than others with regard to long exposure DSO work, I am afraid I don’t know which would be best. Ian

I have currently set it at 105mm. Tomorrow I will try measuring the focal length as suggested by @michael8554

Rumour has it the the sun may come our here (briefly) tomorrow so I will try as you suggest. Thanks for the help. Ian

That's good to know as I guess the Meade is similar in design. I am just used to trying to be very precise with flatteners for refractors so it goes against the grain for approximate measurements!

I recently obtained a secondhand Celestron C8 and Meade focal reducer/flattener and am now searching around to try an find details on the back focus for the Meade reducer. There are many posts saying its not the greatest reducer on earth but little on back focus. One post on Cloudy nights suggested 105mm. I had a look on the Meade website and despite listing the reducer I could not fins any instructions or guidance documents. Does anybody know the correct answer or have any guidance? I am interested in trying the scope with reducer as a reasonably fast scope for galaxy astrophotography. Thanks, Ian

Just an update as I now have the firmware upgrade sorted. I contacted QHY and raised a ticket and I have to say they couldn't have been more helpful. They asked questions and I answered, there responses always being within 24 hours. Ultimately they couldn't see what I was doing wrong so they asked me to download Anydesk onto my PC and give them permission to do the update for me remotely which they did and it worked. Excellent support. It appears that for reasons I don't understand the Hex file needs to be on your desktop not in a folder. If it is in a folder, even it you navigate to it, the upload fails. Hope this information might help someone else trying to do the upgrade. Cheers Ian

My first attempt at the Rosette neubula with my new QHY268MM camera and using Astronomik narrow band filters. Image consists of: 19x 180S Ha 50x 180S O 50 x 180S S The images were captured on the 14th and 15th of January. Processing was me watching some videos on Youtube and 'just having a go' (much to learn) but its a a start!!

It’s a while since I downloaded it but yes I think that’s the site. The software doesn’t look like that when installed. I cannot recall warnings about safety but it was fine. I also know many people use it for planetary. Ian

You might want to consider trying Astrosurface as another free software package. I think it gives you greater control with both wavelet sharpening as well as other sharpening tools. I have used it mostly with my more recent Jupiter images and found it very useful. Ian

Thanks for your response and you comments are helpful. I will just have to keep plugging away with the leaning curve. Thanks, Ian

Thanks for the Youtube link, its very useful. I did buy the Altair and use it with an Altair 26C camera. I haven't regretted the purchases for a second. I get pin sharp stars and don't have to think about flattener back focus. Ian