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teoria_del_big_bang

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Posts posted by teoria_del_big_bang

    Guide / Finderscope focus

    in Getting Started Equipment Help and Advice

    Posted

    7 minutes ago, malc-c said:

    I'm missing something here... why do you need to correct  (erect) the star image when used as a guide scope ?  -

    You don't,
    I was a bit confused also but I think currently the OP wants to still use the Finder/Guidescope as a finder for visual use and the guidescope is just a future plan.
    That's how I read it anyway after a 2nd read through, I guess @Penumbrella will explain when on line again 🙂 

    Steve

    • Like 1

    Hello from Harrogate

    in Welcome

    Posted

    Welcome James to SGL, were practically neighbours 🙂 

    Although dark sites are far better for any astronomy (whether observing or imaging) it is not essential for astrophotography. and in fact most images on SGL will not be from dark sites at all and some from in and around very light polluted cities so you can still get some great images of many targets from your back garden or patio.
    However, which ever route you eventually take starting with visual is probably the best any way
    I started thinking I would only do     visual and bought a secondhand dobsonian, and found that a great start to learn where some of the things are in the sky and get some great views, eventually I did then cross over to doing mainly AP.

    Steve

    ZWO ASI 2600MC - Coma Corrector Spacing - CCDInspector

    in Getting Started With Imaging

    Posted · Edited by teoria_del_big_bang

    I am no expert but to me I would say it has some tilt.
     

    Top right look pretty round.
    image.png.ab03a39b37a961bedcf1ee3787891e73.png

    Bottom right look fairly round
    image.png.4b594638fc1c6fe76146607ee058c1b1.png

     

    Top Left look  a little elongated that could be caused by incorrect BF from CC
    image.png.25010138485d5804b3f83f346fd916bf.png

     

    And bottom left also look a little elongated.
    image.png.3f0154459ec50b95d452412b6aa96d0f.png

    This camera is a fair bit heavier than the 1600 so with a stock focusser could cause tilt (not that I know you have a stock focusser).

    Steve

    • Like 1
    • Thanks 1

    Starlight finder scope mount UNC screws

    in Discussions - Scopes / Whole setups

    Posted · Edited by teoria_del_big_bang

    7 minutes ago, Deadlake said:

    UNC and Imperial I thought where different.

    UNC is just a type of imperial thread sizes (Unified National Coarse) and so is dimensioned in inches and requires imperial allen keys.

    There were are many different types of imperial threads UNC, UNF, BSW, BSF are probably the common ones. Since Europe went metric they are not very common in Europe but many things manufactured in US for example still have imperial threads.

    Steve

    • Like 1

    M101 feedback

    in Getting Started With Imaging

    Posted

    18 minutes ago, Felias said:

    Personally, I have found that using starnet seriously damages my photos. Maybe it's my noisy data, but the circles around the stars are horrible, the pictures end up looking like Emmental cheese -and I suspect it increases the noise as well. You can see those circles clearly in your photo above; it's bad enough for the bigger stars, but those around the smaller ones create a "foamy" background or red and green noise. I now use a star mask in photoshop to protect the stars; it works fine, especially if after each stretch one uses the 'fade' function, and doesn't create such artifacts.

    I did a few tests on a recent image that was proving particularly difficult to make starless due to 2 very bright stars and found that Starnet2 worked much better then Starnet but StarXTerminator using AI StarXTerminator.7 was by far the best and that doing it at the linear stage also worked much better than the non linear stage.
    I think that it does pay to play about a bit with the different methods of making images starless as they can produce vastly different results, some certainly not favorable, and to be careful in Starnet2 and StarXTerminator to check the linear checkbox if data has not been stretched (I think the results indicate quite clearly that you forgot to do this if you do forget).
    But I do agree that making starless images without artefacts is not always straightforward and I think some targets work better than others.

    Steve

    • Like 1
    • Thanks 1

    Camera Rotator - why would I want one?

    in Getting Started With Imaging

    Posted

    46 minutes ago, Padraic M said:

    I replied too soon! 🙂

    Good to know that. I had assumed that if you want automation including an electronic rotator, you would also have to add a flip-flat-type flat panel so that flats could be taken automatically as part of the sequence. And those flip-flats ain't cheap!

    No, but I did add one, also DSD and very happy with it, no affiliation to DSD so sorry to go on how good I have found them (for the price) but for the price it is a great panel, by altering the light intensity instead of exposure length, which NINA can do automatically, I can get all flats 3 seconds exposure length and therefore use the same 3 second master dark from a dark library.
    However (don't want to go off topic too much)  I have seen one issue where by it can collect a lot of dew through the night and then when it closes it dumps it all on the lens and you get very strange flats.
    Not tried it since but I am hoping a combination of change of angle of the flip flat and also making sure the scope is flat before closing the panel will sort that out.

    Steve

    • Like 1

    Camera Rotator - why would I want one?

    in Getting Started With Imaging

    Posted

    1 minute ago, Padraic M said:

    Do you bother with separate flats for the two rotations? Does it make a difference?

    Sorry I edited the post to add the following which you must not have seen 🙂 
    As already mentioned though ideally you should use separate flats for each of the rotations. In practice when I check I see very little difference between flats at different rotations as I think most of the visible dust bunnies and vignetting seems to be cause by things after the rotator (filters, CCD) but still when I can I do take separate flats and so it is a good idea to add the rotation angle to the image filename (easy in NINA) so you can replicate the same angle for the flats.

    Steve

    • Haha 1

    Camera Rotator - why would I want one?

    in Getting Started With Imaging

    Posted · Edited by teoria_del_big_bang

    Also where an automatic rotator becomes very useful is when adding two targets to the nights sequence (maybe 1st target foes out of view at some point in the evening) that really do need a very different rotation to get them in the correct framing as you can use two previous images, or even use two images found on line with correct framing if you do not have previous images) and the software (certainly EKOS and NINA will) will platesolve and rotate to correct framing whilst the rig was left unattended and you are getting some zzzzzz's in.

    As already mentioned though ideally you should use separate flats for each of the rotations. In practice when I check I see very little difference between flats at different rotations as I think most of the visible dust bunnies and vignetting seems to be cause by things after the rotator (filters, CCD) but still when I can I do take separate flats and so it is a good idea to add the rotation angle to the image filename (easy in NINA) so you can replicate the same angle for the flats.

    Steve

    Camera Rotator - why would I want one?

    in Getting Started With Imaging

    Posted · Edited by teoria_del_big_bang

    Is a rotator  necessary for imaging ? As already discussed No.
    Is it useful to have one ? Well I had a bit of cash built up due to birthdays and so on and bought one and I love it, so my experience is yes they can be useful.
    When imaging targets that only just fit in the FOV (Heart Nebula springs to mind) then it really comes into its own, and although I have not ventured into mosaics yet from what I have seen in NINA especially it makes taking a mosaic so simple even in one sequence.
    But then again as

     

    @Adreneline says then this ease in NNA of doing mosaics could be used for any image and then crop.
    Smaller targets then it makes no difference as quite often a fairly hefty crop takes place anyway so not to drown the target with background.
    Also not everyone has the advantage of manual rotation by rotating camera, I didn't as everything was fixed from focusser down to camera. There is supposedly a manual rotator on the Esprit 100 but I could never get the thing to work as it took so much effort to loosen the thing on the first place and then if you did not tighten it enough it moved so easily so I never even tried to use the scopes rotator.
    So I guess for me the question would be is it worth £500+ for the ease of rotating the framing from your laptop.
    And, secondary is if doing mono and already have a filter wheel in the train how easy can you fit one in the BF ?
    I had a pretty thin FW (18 mm I think) but only had a small distance to fit a rotator and originally bought the Falcon which according to the spec should have just fitted with 1 to 2 mm to mess with small spacers to get the BF spot on but when it arrived it was thicker than the specification and with an adaptor was too thick to fit in the train without violating the ideal BF in the end I got the DeepSkyDad rotator, probably the cheapest automatic rotator on the market and it fitted just fine and so far not seen any issues with added tilt and works flawlessly with many sequence software (I have used with NINA and EKOS).

    Steve

    • Like 1

    Top 10 things to make with a 3D printer

    in DIY Astronomer

    Posted

    Regarding the misconceptions of PLA I always thought that manufacturers of things such as PLA cups and other disposable everyday objects actually manufactured the idea of it being biodegradable  to sell their products. 
    I guess reading the technical stuff in theory it is biodegradable in very exceptional circumstances that do not naturally occur and certainly not in landfill.

    Yes, it does degrade and over time it does become more brittle, but so do most plastics.

    So as said previously I would say use PLA if you need something particularly stiff (well as stiff as you can expect a plastic to be).
    I tend to use PETG a lot I like the way it prints and for many thinks I like the slight flex it has as is prevents it breaking under a lot of circumstances but then if I do need something that does not flex so much I would use PLA without hesitation.

    ABS I just gave up using years ago as I could never get objects of a reasonable size to stop warping.

    Steve

    IC443 Jellyfish Nebula

    in Imaging - Deep Sky

    Posted

    11 minutes ago, ollypenrice said:

    I think your OIII is working beautifully to bring out what is a very faint outer shell, often missed by imagers doing this target. I know the OIII features are not 'in your face' but I really think they lift the target. The colour variety is good. Mine is in LRGB with Ha and OIII and, apart from the OIII shell, the rest of the nebulosity is very samey in colour. I might ease off on the saturation, though!

    Olly

    Thanks you Olly, that means a lot.
    i intend to go though the processing again and will reduce the saturation a bit 🙂 

    Steve

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