bomberbaz

4 hours ago, symmetal said:

Astronomik do an H-beta filter in their visual filter range, at a reasonable price, with a pass band of around 14nm, so i thought it could be interesting to try it on the RASA to settle the argument 😁 as it should capture the fainter data reasonably quickly.  At that pass band the fast optics may not be such a problem, compared to their 6nm filters.

Wondering what the difference between visual and imaging narrowband filters was, it turns out that the visual filters don't block IR and need an additional IR blocking filter if used for imaging. This is difficult on the RASA 11 with a mono camera as there's nowhere to fit an extra filter when using the Baader UFC system. I could use it with a OSC camera with its built in UV-IR cut protect glass I suppose, as the green should catch most H-beta.

Alan

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

An hours HB filter data of the western veil, ngc 6960. I don't have any in ha/olll filter as the dew hit my setup and I didn't have any tapes on. Colours not great but I didn't put too much into this at this point.

I would like to see how the two filters results align and what the strength of each looks like for comparison. I had planned to grab 2 hours on each but dew said otherwise.

I do notice the bright halo of the central star which I have never seen before with just the ha/olll filter, curious.

However and overall I am quite impressed with the structure in the nebula but again, a comparison of both is needed and possibly other research/testing on the back of it but it is at least encouraging.

55 minutes ago, IDM said:

Hi My latest version of Siril doesn't have an option for pre-processing with background extraction. Did you write a script or download it from somewhere else? If so could you let me know where.

Thanks

The post you quoted me from has the link to the scripts. Just dl them from the link 

9 hours ago, Bugdozer said:

Finally managed to JUST see the nebulosity very faintly tonight with the aid of the UHC filter. It really is pretty dim. Then I took the filter off and it just vanished. 

The longer focal length eyepiece will really help. Trust me on that

14 hours ago, vlaiv said:

I would say that using arbitrary ratio of Ha signal to reproduce Hb signal is "cheating"

There is no reason to suppose that:

a) this ratio is constant (and indeed it is not) in hydrogen gas

b) this ratio is constant even on selected target

Look at this example:

This is part of M42 taken as OSC image - Red versus Green channel. Red will contain Ha obviously, and Green will contain Hb. There are parts of nebula that are visible in both images - almost the same brightness - which means that Ha to Hb ratio is very close to 1:1 while some other features are present only in Ha - which means that Hb is much much weaker if present at all - and all of this in the same object.

Given that Hb series is higher energy transition than Ha - something needs to excite Hydrogen gas more in order to produce this emission - and I'm guessing that there is some interesting physics behind finding the ratio of the two.

For reference, here is list of visible Balmer series transitions and their color:

Yes thanks vlaiv, I found some interesting comparison from data gathered last night that might be similar in the veil nebula. 

Not had chance to properly have a play around yet ( grandchildren this morning).

There was very little hb in the cocoon though as I suspected, not enough to warrant camera time anyway. 

I think hb imaging is likely to be similar to hb visual in that there are only a handful of objects that will respond well enough to warrant camera time. M43 is one such object, veil may be another. 

1 minute ago, AstroNebulee said:

Hi Steve 

Of course I don't mind. You've done a great job there. 😊 Yes there was a lot of play in the dark levels. Like I say I processed it to be printed from a printing company and use the profiles to check how they print it which would be slightly darker. 

It is a shame I don't have a ha filter but to be fair I can't be bothered with anymore filters, I just like the simplicity of shooting a target and skies have been so poor that a few nights imaging could be a years worth haha. 

Lee 

Can't be bothered with filters, eeek 😨😱, I love using filters as they are fun to experiment and really can add depth an image.  

However I do get what you mean about point and go being so much fun from a simplicity point of view.

Personally I am putting together two images at the minute using two new filters with the aim of having far higher overall integration time and more texture with a little extra colour.

Decent effort Lee. I dl it and had a quick shufty in Gimp, I know you won't mind. 

Anyway, in levels seems like there was a lot of slack in darkness in the levels which I applied, then applied py-astro smart sharpen and wavelets filter.

However you did the hard work of grabbing the data, I reckon a couple of hours with a HA filter would really pull the 3D feel out of that, nice work.

Thanks for the replies all of you but one thing to note, I use Siril and Gimp for processing and although there are scripts and methods of creating SHO type results, most I have seen are not as good as those in PI. 

Also I am using a OSC and just exploring options for adding depth to images over and above those obtained by using the usual DB filters such as the L-ultimate. 

I noted the one member using the SII/OIII  filter getting some fantastic result but again he is splitting the channels to reconstitute in PI. Again, I don't have PI and don't really want to go there.

Anyway, I'll have a play around  as half the fun to me is trying something different and/or learning new techniques. My pet hate is the lack of available information regarding some matters, so god know how people got on before youtube tutorials came along.

Steve

22 minutes ago, DaveS said:

H-Beta filter

Not usually used since the H-Beta signal can be inferred from the H-Alpha.

I understand that but if you are using a osc camera would it not add a different blueish colour than the red from ha?

I know that h beta is difficult to capture and note there are no imaging filters (on flo at least) that are dedicated to imaging in just this wavelength.

Hb/Sll,  Hb/Olll yes but not hb alone.

Has anyone given it a go with an hb visual filter and if so, what joy have you had please?

Steve

21 minutes ago, Bugdozer said:

Just out of interest, do you have a particular 32mm eyepiece you would recommend? As well as the increased exit pupil I am thinking of getting something with a wider field of view, if I can.

Forgot about this. Due to the limitations of the 1.25" system you are at the limits of fov with the 40mm plossl. However it is still giving you a fov of 1.3 degrees which is big enough for the vast majority of DSO.

3 minutes ago, Bugdozer said:

Just out of interest, do you have a particular 32mm eyepiece you would recommend? As well as the increased exit pupil I am thinking of getting something with a wider field of view, if I can.

I was thinking of a plain 32mm plossl, although this still only gives you a 3.2mm exit pupil, that said it gives 70% larger exit pupil.

Personally I would go for a 40mm plossl as this gives you the same fov as a 32mm but a 4mm exit pupil which is considerable 130% larger than what the 25mm offers (and costs less than 30 quid). Astro Essentials Super Plossl Eyepiece | First Light Optics It also still gives a very good x31 magnification due to the long focal length of your OTA. Don't worry about magnification either, x 31 is plenty, I only get x19 with my large bins and it is easily seen with them. A lot of people get caught up in magnification but exit pupil size is the most important factor to consider.

If you do get one in time to revisit the eagle, go to the omega/swan (M17) nebula first, try with and without filter to get your eyes used to seeing obvious differences. It should really pop right out at you, and I mean considerable difference. Then with a short hop goto the eagle with dark adapted eye and you will see it. This is one of those that the longer you look, the more you see. The blinking technique often helps with these fainter nebula in showing up more detail.

Please do let me know how you get on, it would be interesting to know which way you go.

24 minutes ago, John said:

Thanks for the responses folks 🙂

I'm happy with the focuser tilt on my scope so I won't be adjusting it. 

I find that the stock single speed crayford seems to do it's job quite well, even with monster eyepieces. 

 

I think that much of the basic equipment provided to astronomers is more than up to the job John. How easy a whistle and flashing light can and does change how we view things even though it's basic function remains the same.

I used to have no zooms and I think about 25-30 ish fixed length EP's. Personally I now carry less fixed focal lengths EP's than I do variables (4 zooms, I could manage with 2). How times change!

8 hours ago, Lee_P said:

There's a bit of info here. I use a similar technique to the video posted above, but my own recipe! I'll make a processing video sometime. But it's basically about splitting the Ha/OIII and SII/OIII data into their constituent RGB channels, then giving them a stir and making S H O images which you then apply false colour too. It's a dark art!

Yes had a little look this afternoon and also a bit of a play. Problem for me is I only use Siril and Gimp. Gimp automatically splits a fit file down upon loading but it doesn't do a very good job of converting back to colour. I read this is known of Gimp.

I do have access to astap too and AIP4win which both have some functionality in that area but as I am not very familiar with either it's a bit of a curve. 

1 hour ago, Elp said:

There's no real direct comparison with the azgti, but I do find my WO wedge much better still to PA with. The ioptron is so much better engineered as a mount (other than the azimuth locking bolts, I don't like them, they seem to bite into the bottom plate and it knocks off PA so I usually leave them very softly locked after PA (practically loose)). It's nearly whisper quiet in comparison. It's direct equivalent would be the AM3.

You have confirmed what I thought and seem to remember reading some of these points before. (maybe yours even!) I think the HEM15 is my way forward for my objectives.

Anyway, thanks for the reply, most helpful.  

regards

Thank you @Elp for the explanation, with the set up I am considering the load would be close to 8kg so would prefer to air on the side of caution.

I do have a suitable short bar and a 1.25 weight, so I think that would likely be enough to ease both my mind and any topple liability. 

At 600 fl I wouldn't be overly concerned over tracking if it's under 1rms. 

As you know I have the az gti and this is the item under threat along with the 72ED. 

So based upon you owning both mounts, are you happy with the performance of the hem15 vs the Az gti?

Cheers

Steve.

3 minutes ago, ONIKKINEN said:

Stacking multiple nights worth of data is much easier in DSS though, and all the directory creation work can be confusing for a total first timer (such as myself a few years ago).

I use my own scripts for calibration (master darks, master darkflat and a hot pixel map for 60/120/240s data on top of flats and lights, this way i dont have to stack 100 darks each time)    and then stack manually, because the auto stacking scripts is written so that you dont get to inspect the data or choose the registration/stacking parameters. Bit more involved, but this gets the best out of any dataset compared to full auto.

I know what you mean and I manually check each FIT lights file before adding them to the folders, discarding any obviously poor ones.

I store my lights, dark etc folders for siril on a seperate drive so the drag simply copies them to that drive. That way I know I can delete when done safely without losing the masters.

TBH whichever you use can be a faff in one way or another and on my regular clean ups I often end up finding a folder or archive and then ask myself, wonder what that's for? 🤣

21 hours ago, Lee_P said:

Ha, the annoying thing is that the Soul Nebula pic was one of my very first experiments with the SII/OIII filters, and for the life of me I can't recreate the processing steps to get those exact colours! Maybe I'll have to dedicate a day to trying sometime. It's like modern-day alchemy...

Can you explain how you got that colouration to the images please, were they stacked as mono but mapped to the hubble pallette or something along those lines or is that the actual colour you got during data capture. Totally stunning btw!

Has anyone got the counterweight and bar the the HEM15? I ask because when I searched FLO's site for the recommended bar and weight the dimensions look small compared to what they add to mount capacity.

The bar looks to be circa 15-20cm and the c/w is only 2kg. Yet the specs state a near 4kg difference between the two options

Without c/w =  8.17kg

with c/w = 12kg

Has anyone used the setup with and without c/w, what comparisons (if any) can be drawn from experience using it and how does the c/w effect (if at all) the tracking?

Cheers

steve

Ok so found the guide for Siril for you. As @ONIKKINEN says it is super versatile and easy. I stack, then do the processing before finishing it off in Gimp.

Siril - Full image processing (pre-processed with scripts)

These are the scripts I mentioned, I use OSC pre-processing with background extraction which stacks and gives an even background at the same time. You can redo background extraction after stacking if you wish.

15 hours ago, ONIKKINEN said:

 

You could stack in Siril too as it is a bit better and versatile than DeepSkyStacker, but its not nearly as straight forward as the drag and drop simplicity of DSS. So for a beginner my advice would be stacking in DSS, core processing in Siril and then final adjustments in Photoshop. Could use Gimp instead of Photoshop, but i think Photoshop is well worth the money with how many different things you can do in it.

Don't know if you are aware but Siril now has an auto stacking script which is simplicity itself to use.

Simply put the files for stacking in folders on PC and boom, click the script and sit back and wait for it to finish. 

4 hours ago, Bugdozer said:

I got the Astronomik one, because it seemed to have overall positive reviews. I have only had a couple of opportunities to use it since it arrived but not on the Eagle yet. It definitely improves contrast on the things I have looked at so far, although I find focusing with it in a little tricky because you can actually notice the slightly different focal points between the green and red wavelengths. But as they so famously didn't say in Star Trek, you cannae change the laws of physics! 

Same as mine, it is a very good filter indeed. I still think you would benefit a lot with a longer focal length eyepiece to increase your exit pupil but see how you get on. 

1 hour ago, michael.h.f.wilkinson said:

I used a lot of short exposures on my ASI183MC-Pro to get this on M13, in just 1h 38.5 minutes exposure, I think a mix of 60 s and 30 s exposures, but I was using a bigger scope (6" F/5 Schmidt Newton)

That's very nice michael, controlled the stars very well indeed. 

Did you use unity gain and a UV/IR type filter?

Steve

I want to image a few globulars and looking for tips to stop them blowing.

My thoughts are lots of very short exposures but not sure if I should alter gain.

Tips please on this using a 72ed and 183mc pro. 

On 05/10/2023 at 09:26, Bugdozer said:

Thanks for the info everyone. I have a UHC filter now so hopefully that will make a difference, but from the observations with the sketch it sounds like the nebulosity is simply just quite difficult to see without a really contrasty sky.

What make of UHC did you get out of curiosity?