MartinB

This has proved a very popular challenge with a wide range of varying targets. Judging has been tricky with a good number of images being picked. @gorann gets a special mention having submitted numerous stunning images. His total imaging time was about 235 hours, given this was using a dual rig this means that over a period of 3 months he had 117 hours of clear sky. It was very difficult having to leave out some outstanding images. Here are the winners: - 1) Goran 2) Allinthehead 3) The_Bluester To see more outstanding images have a look at the whole thread https://stargazerslounge.com/topic/390022-sgl-2022-challenge-2-dust/

Apologies for the slightly late announceent of this challenge. For the majority of SGL members the next 3 months are a difficult challenge given the short nights and, sometimes, a complete absence of "astronomical dark". We now have a significant number of southern hemisphere members so I will try to ensure that Challenge 6 offers something for them. We are about to come into noctilucent cloud season. For those of you who aren't familiar with these beautiful but elusive clouds you can learn more here https://en.wikipedia.org/wiki/Noctilucent_cloud Entries can be still images or animations. Start date 1st May 2022 End date 31st July 2022 As previously the winner and runners up will receive an SGL challenge mug showing their image along with a virtual medal-of-honour for their SGL signature. Please post entries directly into this thread To keep the thread manageable for the judges please do not post comments about entries, emoji reactions are welcome of course. -- RULES All data must be captured and processed by you (no collaborative entries). Data must be captured during the challenge start & end dates. Multiple entries are allowed but please make a fresh post within the thread. Multiple submissions of the same image, processed differently, will not be accepted.

The challenge is now closed. The results will be announced within the next 2 weeks.

The results are in! https://stargazerslounge.com/topic/393451-sgl-2022-challenge-1-animations/

There was a fascinating selection of entries for this challenge some of which appealed because of the technical challenge involved and others for their aesthetic qualities. 1st Aramacheck Not only is this animation technically well captured but it is superbly presented. 2nd Sleepy Kiki This breathtaking Northern Lights animation might have some of you arranging a winter holiday in Northern Norway! https://stargazerslounge.com/uploads/monthly_2022_03/Aurora_March_2022.mp4.9fa984086247ebaa546da2f26a21623b.mp4 3rd AlexJ The historic launch of the JWT gave a chance to record the telescope at a huge distance from the earth. Well done everyone who managed to produce a very challenging animation. This entry was our top pick. Well done everyone who entered. There are more terrific animations in the original challenge thread. Well worth a look. https://stargazerslounge.com/topic/388392-sgl-2022-challenge-1-animations/

This challenge is now closed. The results will be announced within the next 2 weeks

Start Date: 1st April 2022 End Date: 30th June 2022 The Sun has sprung back to life as part of it's 11 year cycle. The next 3 months should provide solar imagers plenty of opportunities to demonstrate this activity. Full disk, small details and animations all welcome. RULES All data must be captured and processed by you (no collaborative entries). Data must be captured during the challenge start & end dates. Multiple entries are allowed. Multiple submissions of the same image, processed differently, will not be accepted. -- To enter please post within this topic, do not start a new topic. Please post as much information as possible - when it was taken, how it was captured and processed, etc. The info won't necessarily be used for judging but will help fellow SGLers looking to learn and improve their knowledge and technique. The thread is for image submissions only, please do not respond to entries other than by using emojies.

The results are in!

Comet Leonard certainly put on a show. It was quite a challenge from the UK being very low down. The entries were low in number but very high in quality. 1) JP-S says he has never imaged a comet before! Well this isn't bad for starters!!!! 2) Howzat timed this imaging session to perfection 3) This superb animation by Laurin Dave has brought the comet to life. It is well worth having a look through the thread to see some more excellent comet images https://stargazerslounge.com/topic/387141-sgl-2021-challenge-9-comets/

Obviously there are lots of youtube videos some of which are very good, some less so. However, the thing with PI is that you really need to learn in a structured way. I tend to learn through experience and dipping into things as and when I need them but this isn't ideal for something like PI. You really have to get to grips with the interface and the way the tools function and this needs a more meticulous approach. I have pasted linkis to Light Vortex Astronomy which provides this sort of approach and is well thought out. Adam Blocks Fundamentals is very good but Adam's videos do then to send me to sleep. He goes into great details about everything and you have to go at his pace ie slowly. https://www.lightvortexastronomy.com/tutorials.html https://www.adamblockstudios.com/categories/pixinsight

Start Date: 1st March 2022 End Date: 31st May 2022 We are now coming into "galaxy season". Smaller galaxies are very difficult to successfully image individually since they are so small, however they can often be found in very photogenic clusters especially at this time of year. The challenge is to produce a galaxy image containing at least 4 clearly discernible galaxies. A personalised mug for 1st, 2nd and 3rd places featuring your entry kindly provided by our sponsors FLO and a virtual trophy for your signature. -- RULES All data must be captured and processed by you (no collaborative entries). Data must be captured during the challenge start & end dates. Multiple entries are allowed. Multiple submissions of the same image, processed differently, will not be accepted. -- To enter please post within this topic, do not start a new topic. Please post as much information as possible - when it was taken, how it was captured and processed, etc. The info won't necessarily be used for judging but will help fellow SGLers looking to learn and improve their knowledge and technique. The thread is for image submissions only, please do not respond to entries other than by using emojies. If anyone has any questions about the challenge please message me directly rather than via this thread.

That's an interesting project Myles. There is an Anelemma challenge currently running with a duration of more than one year. This is running alognside the regular challenges. I could do something similar for Barnard's Star. I will have a think about that.

The challenge is now closed. The winning images will be announced within the next two weeks.

I'm sorry but all the data has to be acquired within the 3 month period of the challenge.

The votes have been counted and the results are in! https://stargazerslounge.com/topic/390558-sgl-2021-challenge-8-all-about-orion/

Well this challenge certainly didn't disappoint. It was very interesting to see the different interpretations of M42 and it's surroundings. The widefield images magnificently displayed the richness and complexity of this area of the sky. No wonder Orion is many peoples favourite constellation. Just as a reminder, rather than the usual first, second and third placings this challenge only has first places, one for a deep sky object, one for a widefield sky view, and one for sky with a landscape foreground. It has been a difficult choice and there were some splits down the middle when counting the votes. Deep Sky Fegato Widefield Sky Zummerzet_leveller Nightime landscape Emiliano2000 https://stargazerslounge.com/uploads/monthly_2021_12/dd0f7cc6-8203-4e11-8e4b-fd1635e5d64b.png.97f933b17e959925c2a5bad03c244636.png Thank you to everyone who entered. It is well worth having a look at all the images submitted for this challenge. Click on the link below https://stargazerslounge.com/topic/385555-sgl-2021-challenge-8-all-about-orion/

This challenge is now closed. The results will be announced within the next 2 weeks.

Sorry Dave, only a bit of flippancy😑

Does that mean that in the real world a Reliant Robin might out accelerate a Porche 911? 🙄

Could the issue be that you are comparing OSC with mono Dave? In general I would opt for mono nearly every time although the latest batch of colour CMOS cameras with a decent nebular filter and fast optics are delivering some very impressive results. I am posting a Rosette image from 2019 which I hope demonstrates why I am very happy with CMOS. This image was taken with a mono 12bit CMOS camera (ZWO ASI 1600MM pro) using Baader 7nm filters. 30x5mins Ha, 7x5mins OIII and 20 x 5mins SII. The data was captured over a few weeks and there were lots of passing cloud throughout the capture, hence paucity of OIII particularly. I don't think I would have got any data using my QSI 532 which needed 30 min subs to be getting over the read noise hump. I was using a 200mm camera lens at F2.8. Although I was undersampled it was getting into the right sort of range given the the cameras relatively small pixels. I have added a crop which I hope demonstrates that the resolution isn't that bad. There is no way I could have done anything like this with my QSI. I have also attached the Ha mono which shows how well the camera has picked up the faint outer nebulosity, not bad for a 12 bit "re purposed chip" The mount was a little SW EQ35M pro and wasn't behaving itself very well. So, a 200mm camera lens, a pretty basic mount and, by CMOS standards, an old chip. Using this set up I would feel able to use 30 second unguided exposures using my ancient Vixen Super Polaris mount and a cheap old ebay 200mm lens. The door to serious deep sky imaging has been properly opened to would be imagers on a tight budget. Terrible framing, I hadn't realised there was so much nebuloisty over to the right.

Our galaxy and universe is full of dust. So this challenge is about capturing it photographically. Now for members with pristine dark skies this is an opportunity to capture beautiful images of faint integrated flux, however, those under less favourable skies shouldn't lose heart, we are also interested in images showing the impact of dust such as reflection and dark nebulosity along with galactic dust lanes. The muckier the better! A personalised mug for 1st, 2nd and 3rd places featuring your entry kindly provided by our sponsors FLO and a virtual trophy for your signature. Starts 1st February 2022 Ends 30th April 2022 -- RULES All data must be captured and processed by you (no collaborative entries). Data must be captured during the challenge start & end dates. Multiple entries are allowed. Multiple submissions of the same image, processed differently, will not be accepted. -- To enter please post within this topic, do not start a new topic. Please post as much information as possible - when it was taken, how it was captured and processed, etc. The info won't necessarily be used for judging but will help fellow SGLers looking to learn and improve their knowledge and technique. The thread is for image submissions only, please do not respond to entries other than by using emojies.

Robin Glover explains that there is minimum exposure time required to neutralise the effect of read noise. He also points out that there is no benefit in increasing sub exposures beyond this for achieving a desired ultimate SNR of the final stacked image. I have no argument with this at all. When I got my QSI 532 CCD back in 2010 I used the CCDware sub exposure calculator to work out my minimum sub exposure, it was invaluable. However, Robin Glover isn't saying that longer exposures are detrimental. Craig Stark has done a lot of work with CCD cameras examining exposure times and SNR in the real world. SNR continues to increase beyond minimum optimal sub exposure time. The limiting factor is the point where pixel response becomes significantly non linear of brighter parts of the image such as bright stars are becoming saturated. Yes, gusts of wind and rogue clouds give a bigger hit when they ruin a longer sub. Satellites less of an issue for me since I rarely have less than 30 subs per channel. One other issue with short subs is time lost through dithering. You certainly need to be avoiding dithering after every sub otherwise the loss of exposure time becomes substantial.

OOh yes, very true. mine is a ZWO 294mm

I've just been back over some images I've taken with the 294 and I had forgotten that I have previously used 10 mins for NB. Would be quite happy with 5 mins and less. The reason I don't go as short as possible is to avoid having huge stacks of files to plough through! PI's weighted batch processing script stores all the files created at every stage of calibration, that's a lot of time and Gbs! There is no great merit in taking the shortest subs required to overcome the read noise so long as things aren't getting blown out. Each to their own but I am very happy with the results I'm getting.

But I'm sure you vary the iso when doing your day time photography and wouldn't want to be without that option! The 294 has the benefit of that magic "high conversion gain" at a gain value of 120. At this gain you have the same dynamic range as a gain of 0. You just have a slightly lower full well. You won't go far wrong if you always stick with a gain of 120. Some people shooting broadband opt for zero gain in the belief that it can give a better appearance to broadband stars but this is probably dancing around on the head of a pin. I use an offset of 50 and my subs are always 5 mins. With CCD cameras I used to use the CCDware optimal exposure calculator to determine sub exposure time because you really didn't want to have subs longer than necessary. With my 3 cmos cameras regardless of optics I nearly always use 5 min subs with possible exceptions such as M45 and M42. I take an initial sub to check I'm not blowing out my brighter stars. You should be fine using an offset of 50 regardless of exposure time. The "optimum" offset does vary if you change the gain value but the loss of dynamic range from an overly high offset is incredibly small. You can tie yourself in knots with all this stuff but it just isn't necessary -gain 120, offset 50, cooling -10 (no good reason for going lower and kinder on your chip than -20). Match your dark frame exposure time to your lights (uncheck any optimisation of darks boxes) Flats somewhere between 25 and 30K ADU and take flat darks (dark frames which match the exposure time of your flats.) Don't worry if your flats look dodgy it will all come out in the wash! Re green cast, I prefer to correct this with levels since I think HLVG will shift some of the green across to other parts of the spectrum which isn't really an ideal way to treat linear data. The HCG switch really changes the game, things are a bit more complicated with an ASI 1600. If you are in the Peak District let me know, I could ride over on my bike for a meet up. We are off to the Yorkshire Dales later this week.