Alatir Quadband and ST 1.6 beta

[JLP]

I thought it may be worth sharing an image I took using a Altair Quadband filter. It is quite noisy but then it is only 52mins worth.
I did not get the integration time I really wanted although I had the clear skies. The reasons for that is a whole story on its own; funny shaped stars turned out to be sloppy camera adapter and then there was and still is the issue of my iOptron RC6 misting up its mirrors. These were freezing nights.
The net result I have only got 52 mins worth of data targeted at the Bubble Nebula NGC 7635.
My equipment was an iOptron RC6, iOptron CEM 25EC, Altair Quad Band 2” filter and Olympus OMD EM1MKII camera. This gives an imaging scale of 0.5”/px. I used NINA to take images no guiding (NINA direct guider used to dither) and dither between every image. I live in a class 5 Bortle area (25 miles from London)
I took 13 x 4mins exposures at ISO3200 with camera noise reduction on (=13 dark frames), 20 x flats and 20 x Dark Flats and stacked in DSS 4.2.3 using no white balancing processing. The resulting fits file was processed in ST 1.6.386.
I mainly accepted the default settings and am not sure how this image measures up but it is surprising how much colour and detail there for short integration.

[admin]

Really appreciate the report and share! Quad/duoband filters are just fantastic for astrophotographers like yourself under light polluted skies.
I'd say your image is still somewhat oversampled at this resolution. Binning (more?) may help reduce noise further, while possibly also make deconvolution possible.
How do you find your Olympus camera for low light situations generally? I have not come across too many datasets for this model.

Clear skies!

[JLP]

Hi Ivo
For me the jury is still out on the usefulness of the Quadband filter. I need to get a good set of data of a couple of hours. I got the Quadband so that I had some protection between my RC6 and camera sensor. I once forgot to check the clouds and it rained luckily I did not get the sensor wet but the mirrors on the RC6 did and needed cleaning. With my Olympus 300mm f4 lens I have had some ok results but always looking to get better images and have a wider choice of targets. The RC6 and CEM25EC are recent additions to my hobby. I have put some images on https://www.astrobin.com/users/johnparker33/

I normally bin 25% for speed and have been choosing conservative deconvolution. I am still learning about oversampling and what effect it has. My Olympus I think is OK for low light for a cropped sensor. It has some features such as a composite mode where it updates the image only if the pixel increases in light value, meaning you can create a star trail in camera. It also has a live boost mode which increases the gain so you can see stars or milkyway better. I had been happy with the sensor performance up until recently but it turns out that as my tracking and polar alignment have got much better it shows up fixed pattern noise of the sensor.

I use Olympus because that is my choice of camera equipment for shooting wildlife and motor sports etc. It is light weight with good optics and excellent image stability, none of which is any use for astrophotography. Olympus is a difficult system to integrate with astrophotography software but I have been introduced to NINA which allows me to watch a folder where my Olympus raw files are saved and so almost simulates an astro camera.
At the moment I have nothing to compare sensor performance with. When I was using my Star Adventurer tracker the Olympus sensor seemed ok. Then I got the iOptron CEM25EC mount (encoders) and my stacked frames highlighted the fixed pattern noise of the sensors I have an EM5 and EM1 both MKII's. I am seriously considering an mono astro camera with TEC cooling and a narrowband filter set, but at the moment I want to see what I can get with my RC6 and Olympus cameras on the CEM25EC.

[JLP]

I had another go with the Quadband filter on the Cigar Galaxy M82 last night. There was a 90% moon and I captured 3hrs 22mins worth of 4mins ISO1600 with a Olympus EM1 MKII and iOptron RC6 on a CEM25EC mount no guiding. took 15 darks 20 Flats and 20Dark Flats. Processed in DSS 4.2.3 no WB checked and ST1.6 using composite mode lum RGB all using the same stacked file but doubled the exposure for the green. Do not know how true the colour is but did do some tweaking to defaults. Did finish off in Lightroom 6.1.4.