PhotoGav

+1 for APP.

Yes, variables and more variables! I am a CCD user and don’t have any experience with the newer CMOS technology. There is plenty of advice available out there though. As with all of this, the only real way to find the answers is through real world experimentation. Good luck with it! What I failed to mention in my earlier post are the the two approaches to multiple sub lengths on the same target. The first is as I believe you have done, ie deep subs with slightly different exposure times - mix in one integration. The second is two sets of subs at different lengths to expose for different areas of a target - process separately and combine in an HDR fashion in Photoshop or similar.

Doh! What a relief to find the 'simple' solution though!

You certainly can mix subs of different exposure lengths. Which software are you using for stacking? As you say, just make sure you can assign the correct darks to the different subs and all should be fine. As for narrowband sub length - as you are discovering, the longer the sub, the better the signal detail captured (in general). The question becomes how long is long enough? There is a trade off between signal / sub length / tracking accuracy / sub lost due to something going wrong / number of subs captured in available time (as the more subs the better for stacking) / max exposure time with your set up, and probably more variables! Personally I tend to use 1800s subs for narrowband, and still feel that I would like to go longer! Good luck and I look forward to seeing the results.

Thanks Daz!

Thank you. I’m just a few months late with my entry! Thank you. Yes there is definitely something faint and fuzzy just below M12. Looking on Sky Safari - it is PGC 1103219, a 15th mag galaxy about 870 million light years away!

Over the summer I have been acquiring data for various globular clusters. I already posted M92 back in June and here are three more completed images for you to compare and contrast: M12 16,000 light years away in Ophiucus M56 32,000 light years away in Lyra M71 13,000 light years away in Sagitta M12 & M56 have one hour in each of R,G & B and M71 has two hours in each channel. I have combined all subs to make a 'SuperLuminance' layer in each image - I find that this works pretty well to maximise the data and improve clarity a bit. All were captured through a Celestron EdgeHD 8" on a Mesu 200 mount, with a QSI 683-WSG8 & 31mm Astrodon filters. Processed with APP and PS CC. Some say that all Globular Clusters look the same, but I hope this selection goes some way to changing your views on that! Most noticable is the difference in the star fields between the three images, starting on the edge of the plane of the Milky Way with M12, getting closer with M56 and right in there with M71. M71 is also known as The Angelfish Cluster - can you see him... swimming up to the left towards about 10 o'clock?! I look forward to hearing what you think and in the meantime... clear skies!

Well, that’s good news! Conclusion: computers are strange....

I use Sky Safari Pro (not free) on iOS, which has the camera / telescope combination rectangle overlay to see what your potential target will look like in your field of view. You can save your range of setups and display all simultaneously, thereby helping to decide which setup to use for a particular target. You can also save observing lists of targets, with notes, that can be highlighted in the Sky view. It’s just a great portable planetarium and is currently on offer for only £19.99 in the App Store! (I’ll add that I’m not on commission...!). I use Cartes du Ciels on the obsy PC, but mainly just for slewing to objects, though it does also have the combo rectangle overlay feature. I look forward to seeing the article.

Absolutely John, it was constant flickering for quite a while over the western horizon, probably right over you, before it arrived here!

Well that was some night last night... the All Sky Camera caught this:

Deep Sky West (Midlands) - absolutely love it!!! Good luck with the build, I look forward to seeing the progress updates.

I’m sorry to say this, but... I have no idea!

Ouch... too close for comfort. More details are required to suss out what the problem is. Which version of SGP are you running, have you updated it recently? Can you post a log file and maybe a screenshot or two of the relevant settings screens please. Have you posted on the SGP forum too?

I can highly recommend the Big Daddy Box Meal at KFC, it really is something special...!! Look forward to seeing you at the party.

Perfect, thank you Alan, with your encouragement I will give that a go!

Thank you Alan. I have Aladin and have tried to use it in the past, but found it very confusing and gave up embarrassingly quickly! I will give it another go. There must be a decent tutorial for it somewhere...

Hah, thank you! Thanks Rodd.

If you find a good solution... please let me know! (And please don’t say PI!)

Thanks Tom.

It is a bit more expensive, but having been through about four useless USB hubs prior to this one, I wish I'd gone straight to the StarTech!!!

I use a Startech USB hub (https://www.amazon.co.uk/StarTech-com-Port-USB-3-0-Hub-Black-Metal/dp/B00SCE4E0I/ref=asc_df_B00SCE4E0I/?tag=googshopuk-21&linkCode=df0&hvadid=309981988222&hvpos=1o27&hvnetw=g&hvrand=71678861840839942&hvpone=&hvptwo=&hvqmt=&hvdev=t&hvdvcmdl=&hvlocint=&hvlocphy=9045600&hvtargid=pla-348690807809&psc=1&th=1&psc=1) and power it on and off remotely through a Wemo Switch with no problem. Worth considering.

One of the issues is that there have been all sorts of small changes since a lot of the tutorials were made so buttons aren’t there any more or have changed. All the sliders can be quite mysterious and sometimes pretty subtle in their effect. Thankfully the majority of it works well on the default setting. The one thing that I struggle with sometimes is efficient satellite trail removal. I quite often just exclude subs with trails as they tend to leave a faint remnant whatever settings I use.

You did well to catch that - it has now been ejected far our into space... shame you didn't do a time lapse of it! Have a look on GONG (http://halpha.nso.edu/) and click on the film canister icon of the El Teide feed and you can see it all unfold (literally!).

Yup, there was a large ejection at around 09:00 UT this morning - looks like you've caught the remenants leaving the Sun! Check out the images on GONG - http://halpha.nso.edu/ If you click on the film canister icon in the El Teide image section, you will see it all develop and depart - it's quite amazing!