Search found 793 matches

by oopfan
Mon Dec 21, 2020 8:47 pm
Forum: How do I?
Topic: Taking bias frames?
Replies: 12
Views: 311

Re: Taking bias frames?

Scott,

Like Darks, Bias frames require for you to cover the objective. If you don't then a bright star like Alnitak will still cause a print at 1ms exposure.

Brian
by oopfan
Mon Dec 21, 2020 8:26 pm
Forum: How do I?
Topic: Taking bias frames?
Replies: 12
Views: 311

Re: Taking bias frames?

Hi Scott, Sorry to say that this is out of my range of experience. I'm old school: I use SharpCap to capture lights, darks, flats, and bias as individual files, and then I calibrate and process in Astro Pixel Processor (APP) but I've also used DSS. I replied because you mentioned DSS in your origina...
by oopfan
Mon Dec 21, 2020 7:35 pm
Forum: How do I?
Topic: Taking bias frames?
Replies: 12
Views: 311

Re: Taking bias frames?

Scott,

If your bias files look normal, is there a possibility that you added them to your DSS project as something other than "offset/bias files"? Perhaps you accidentally added them as light files?
DSS Bias.jpg
DSS Bias.jpg (63.8 KiB) Viewed 175 times
Brian
by oopfan
Mon Dec 21, 2020 7:06 pm
Forum: How do I?
Topic: Taking bias frames?
Replies: 12
Views: 311

Re: Taking bias frames?

Scott, Are you Live Stacking or capturing in a traditional manner? Perhaps if I could view one of your bias frames, I could help. Did you capture in FITS file format? If so, then download and install FITS Liberator, open your bias file, and take a screenshot. The histogram will tell me a lot. Thanks...
by oopfan
Sun Dec 20, 2020 8:40 pm
Forum: Gallery
Topic: Jupiter & Saturn, optimistic imaging
Replies: 14
Views: 478

Re: Jupiter & Saturn, optimistic imaging

I like the "well-exposed" shot of Jupiter, it's moons, and Saturn. It really shows how close they are. Sometimes we can't make pretty pictures, but there is always valuable information in there. This hobby is even more enjoyable when we recognize that there is science in every frame we tak...
by oopfan
Sun Dec 20, 2020 8:24 pm
Forum: Gallery
Topic: Jupiter & Saturn, optimistic imaging
Replies: 14
Views: 478

Re: Jupiter & Saturn, optimistic imaging

As my stepmother would say: "It was one of my lesser successes" which revealed her optimism.

An excellent showing for 5 degrees above the horizon!

Brian
by oopfan
Sun Dec 20, 2020 6:30 pm
Forum: Tips and Tricks
Topic: A Scientific Approach to Narrowband Imaging
Replies: 5
Views: 549

Re: A Scientific Approach to Narrowband Imaging

Thank you, Dave. Excellent images! The Dumbbell Nebula is a planetary nebula, so we have access to its spectrum, courtesy of Professor Karen B. Kwitter, Williams College: https://web.williams.edu/Astronomy/research/PN/nebulae/index.php I've zoomed in on the area around the hydrogen-alpha (Ha) line: ...
by oopfan
Sun Dec 20, 2020 1:55 pm
Forum: Tips and Tricks
Topic: A Scientific Approach to Narrowband Imaging
Replies: 5
Views: 549

Re: A Scientific Approach to Narrowband Imaging

Robin, The only problem with the photometric method is that the ratios change with the bandwidth of the filters. For example, a 3nm Ha filter will isolate the Ha emission line, but a 7nm Ha filter will also capture two nearby NII lines. The NII lines are just as strong as Ha in some nebulae. The bes...
by oopfan
Sun Dec 20, 2020 5:39 am
Forum: Tips and Tricks
Topic: A Scientific Approach to Narrowband Imaging
Replies: 5
Views: 549

Re: A Scientific Approach to Narrowband Imaging

Hi Robin, Yes, the total integration time of SII will be seven times longer than Ha but only if we choose a long exposure for SII so that the per-sub SNR is the same as Ha. In reality this is impractical, so we need a longer integration time for it. Regarding light pollution, I am assuming that it i...
by oopfan
Fri Dec 18, 2020 6:56 pm
Forum: Tips and Tricks
Topic: A Scientific Approach to Narrowband Imaging
Replies: 5
Views: 549

A Scientific Approach to Narrowband Imaging

It is that time of year again for the Tadpole Nebula in Auriga. Last year was my first attempt at it. Sara Wager inspired me with her exceptional image using Ha and OIII. https://www.swagastro.com/ic410.html Like most people, I chose a single exposure and then captured an equal number of frames. It ...