bomberbaz

That is a rather obvious but brilliant piece of advice. Too often I have finished after an unsuccessful hit attempt at something difficult and thought, " what the hell, home time". Better to think, "wow, that was good, time to head back". thumbs up!

yeh but tomorrow it's lunar eclipse day 🙄

alas I fear the weather gods will be conspiring against me on that night!

Seems us older chaps adopt similar, my biggest exit pupil are at 5.3 (age [cough] 60) as a future proof should see me good for circa 10 years. But this wasted light discussion brings us back to my rationale for adopting a larger exit pupil in the opposite way, maximise your light grasp when needed (when using light limiting filters) on dimmer nebula dso.

Just to help here it was I who suggested a reducer for increasing the exit pupil for use with narrowband filters in a different thread. The op was looking at viewing the eagle nebula and was struggling to see it with no filter and a 25mm ep at 2.5mm exit pupil. It was suggested by one commenter that a uhc filter would help but I chipped in with reducer for the larger exit pupil or a 40mm plossl as an additional measure to improve results. My personal experience points to a 5mm exit pupil being optimum for line filters with 4-5mm being ok for the more forgiving uhc when used on diffuse nebula. I have read numerous articles in various forums and have yet to find anything to convince me otherwise. So if you can live with the vignetting to have a strong response from a dim object at the centre of the eyepiece then it is still something to consider, a 40mm plossl is the other contender.

@ONIKKINEN many thanks for this, I shall have a bash at this with what data I have and see what I come up with. In the interim I found some excellent tutorials on YouTube by one guy who covers a broad range of subjects and goes through them with a Janet and John style for relative novice users to follow. My only problem is trying to remember them all🤣

Up to this point I am fine and it is easy enough to follow, I have done script editing so this is all stuff I am familiar with. It is the stuff below where we are getting into pixel math where my head starts to hurt. However, I think I shall give it a whirl first before I start asking for further help as I am keen to learn new methods. Above you mention that this is a relatively simple operation to carry out with [photoshop, do you know if similar functionality is available within gimp or not? If you have a video link to the photoshop version I may be able to translate it over to Gimp! Cheers and thanks for the help thus far, very much appreciate it. Steve

I can confirm old age is well and truly set in with me. I was going to save the cruxis link to my favourites but when I tried my browser informed me I already had it saved. Make way for me an the nursing home 🙄😂

And as often happens I have opened an astro Pandora's box 🤣

So it does, my bad missing it. Cheers stu

Yes the idea of modifying the script had passed my mind but given the above, where do I go from there? What program would you use for stacking the data as one or is there another process you could suggest. I mean I could use a universal exposure but this leads to other problems too! This (stacking data) is a science in itself and I am struggling with some of it, well actually everything 😭🤣🤣

Thanks John and @Stu for these. I agree entirely with the altitude being a strong consideration but also and as mentioned by @Mr Spock, localized lp. Stu's cruxis.com calculator asks for either brightest star at zenith or sqm at zenith. Now this is great if you have a fairly even sky in all directions, but if like me you have really bad light pollution in one direction but reasonable skies in the other your going to run into issues as you hunt out you object, more so as you drop down in altitude where I think once you get below 45 degrees it gets increasingly problematic. So either I stick to one half of my sky or take multiple sqm readings and in doing so add another layer of complexity before even looking at John's atmospheric calculator! There really is no easy answer to this I am afraid. Cheers all Steve

Thanks Stu, I shall have a play later on my pc

Ok I know as do most seasoned observers that light pollution has a huge impact on nearly all objects bar lunar and some planetary. I no longer even bother with any local deep sky observing due to light pollution and even narrowband viewing is not particularly rewarding and not really worth the effort. Also I have lost count of the number of occasions I could have had impromptu sessions in the back garden when forecast and weather haven't agreed or just a couple of hours of clear weather have graced the evening. It is such occasions I think I need to be taking more advantage of. So I think I will encourage myself to target more planetary viewing using the 100ED and also think I will join in the 60mm frac double challenge that I have been loosely following on this forum. But what I want to know is, what is the guide / formula etc that provides the following: "magnitude = aperture - bortle less local light pollution" (if indeed such exists) so I can segment as it were my viewing list(s). No doubt similar queries have been thrown out before, and tbh feel I should know better myself but it is always good to get a fresh take on such things so any help will be gratefully received. Tia steve

There you have 4 replies and all different and none either right or wrong, it is all a matter of personal taste. As you already have a Barlow you have that flexibility already so a fixed length eyepiece could be used to cover your needs we with the added advantage of doubling your focal lengths with said Barlow. You have not given a budget so @Spile's zoom suggestion is both low priced and very good in quality department. I personally am a big fan of zooms and if your budget is larger then the baader Mk IV zoom is a superb bit of kit in all departments albeit a little pricey.

Mine came with an 18mm pair supplied so I bought 10 & 24 to supplement them. I also got some 30mm plossl but these were purchased for the exit pupil size (5mm) as they work well with nb filters. Next I got some 8mm starguiders as these offer the highest recommended useable magnification (x58) without dodging into CA territory of plus 60 but have to say the 24,18 &10 get most usage. The 8's may yet go.

If u ever get the chance of a uff 24, get it. The uff are on another level, I use them in my big bins and my dob, they are superb.

I recently downloaded the one shot colour stacking script, it is a massive time saver for me and tend to use it. I am preferring it as my go-to now but have a query. If I grab multiple exposures data at eg 120 seconds with ha filter and 30 seconds at luminance, will it pick up both sets of data and stack or just one? Tia Steve

Rude

Agreed, I had one of these, still have the 9-27 version and it's a great bit of kit and under budget giving up to x210 which is close to the limit for the 127 anyway. https://www.firstlightoptics.com/ovl-eyepieces/hyperflex-72mm-215mm-eyepiece.html

Hello. I was grabbing some data just to waste away an hour on the celestial snow angel and I noticed what "appears" to be nebulosity around Cyg 44. I have not noticed this before, stellarium shows nothing although a couple of online references do show some nebulosity too. However although there is visual evidence I cannot find anything written about this. Has anyone anything they can add to this because I think the reflection nebula (if it is) and the angel would make a nice pair together if positioned correctly.

Added to extra hour so shade under two hours total, very pleased with this although may have pushed it a little too far, maybe used with star exterminator but that can wait til later, it's not the main purpose of the exercise. Hoping to get same amount of HA/OIII data tonight, compare like for like and then combine.

I would be looking at the HEM15. I too am looking at the quattro 150p and it will marry really well with that mount.

I really do not understand what this means. I am using a refractor though if that makes any difference! The h beta used was a cheapest svbony version I picked up somewhere down the line, remember thinking yesterday I should have used the astronomik one although both are visual and I do not know how tight the bandpass is. EDIT Both claim to be suitable for either visual or imaging but both say use a IR/UV cut for imaging and as mentioned I use an L2 filter for this. So still slightly perplexed re the halo.

Never saw this reply. My image above had an L2 filter installed at the filter nose, still managed an halo!