groberts

Can somebody reccommend where I can get a suitable step-down ring(s) / aperture stop ring to use with the Samyamg 135/f2 lens - I'm thinking of ~2.8 or 4.0?

Graham  

OK thanks, I completely understand the principal but need to clarify some details please:

• Is the 44mm back focus taken from the flange or the rear optics of the lens? 
• Either way, it seems to mean a spacer of about +/- 17.5mm:  44mm minus (camera sensor to EFW 6.5mm + EFW 20mm).  If this is correct can somebody point me to a suitable source of spacer i.e. M42/T2 male + female, to screw onto the lens adapter at the front and the EFW behind.  I'm thinking slightly shorter so that I can then use thin spacers to finesse the distance if required, if that makes sense?

Would still like to hear from anyone who has the ZWO 1600 camera + ZWO EFW + Samyang 135 set-up and what their experience and solution to this issue was?

Graham         

Good news, thanks.

Whilst I'm on the subject, can anyone recommend a set of step-down rings that will fit this Samyang 135/f2  lens?

2 hours ago, newbie alert said:

My understanding is the backfocus of a canon version is different to the Sony.. so better clarify what one you have otherwise its not going to work

Not sure I understand your question but if you mean the adapter it's an NSA M42/T2 which replaces the Canon fitting fitting on the lens and screws directly into the EFW providing a more stable connection betwen the lens & EFW:  https://ensoptical.co.uk/index.php?route=product/product&product_id=13220

Otherwise everything else is standard ZWO camera and EFW.  Hope that helps?

Graham 

I'm planning to fit my Samyang 135/f2 to a ZWO ASI1600MM-Cool camera via a ZWO x8 EFW with ZWO filters using screw in M42/T2 adapter between the lens and EFW. 

I'm fairly sure that someone will have this popular set-up and would appreciate guidance on focussing - will I need any spacers etc to achieve focus, if so what thickness?

Graham 

Over an eight week period from mid-January this year, very unusually I managed four images with total integration time of nealry 55-hours!  I appreciate that this is nothing to some but if you live in the UK close to Gatwick airport it's quite a feat, certainly unprecedented for me during the time I've been doing this astrophotography malarky! There are therefor more in the processing pipeline, which works very slowly here, but after Lowers Nebula posted here in March, the next one off the production line is the Horsehead Nebula.  

The dark silhouette of the Horsehead Nebula against the surrounding rich HII-region, is one of astronomy’s most iconic images.  Surprising then that I’ve never imaged this object in broadband wavelengths before with my mono camera: the first image was in February 2015 using a modded Canon 55OD camera, then in January 2018 with the ASI1600MM + narrowband filters and most recently in January 2021 using a widefield Samyang 135/f2 rig and modded Canon DSLR.  Therefore, somewhat belatedly and with the aforesaid long spells of clear skies, this February I set out to rectify this omission from my astrophotography repertoire and am pleased with the result - hope you like it?

Graham

Image Details: WO GT81 + ZWO ASI1600MM Cool camera

x35L x35R x34G x35B @120s exposure

x 78Ha @300s exposure

Total Integration: 11hr 8min

Can't recommend this scope enough but one small issue - I've always found the focus lock screw a bit too weedy i.e. difficult to get good purchase on the small knurled knob to lock it down firmly.

Does anyone know what the thread size / type of this is + a source for a replacement with more bite i.e. probably just a better knob which provides better purchase with which to lock it down?

Graham

FYI here's the HOO version - I prefer the SHO-HOO colours + brings out more detail

Thanks for the comments + keep persevering.  IMO this is an interesting & rewarding target, only surpised it doesn't get more attention.

Graham 

Located in the outer regions of the Orion constellation above Betelgeuse, Lower's Nebula consists of mainly ionized hydrogen.  It’s surprising that this interesting, quite large but faint object does not get more attention from astrophotographers, who are perhaps too busy collecting photons from the more famous objects that flourish within nearby Orion itself?  For once clear skies were abundant here during January which allowed for some 17-hours integration time, albeit mostly accompanied by a waxing to full moon.

The data lends itself to various processing approaches and I played around for a long while with a number of different combinations, in the end favouring an SHO + HOO blend as the main image and am pleased with the result.

Graham  

Ha 44 x 600s

OIII 30 x 600s

SII 28 x 600s

Some were, some weren't.

It's embarassing but it seems like it was just overexposed and I wasted +5 hours imaging time, but I still don't really get it?

Spent two days checking setup and, as far as I can see, all's fine.  So with clear skies went out again on Friday and tried exposures at 300s = better, 180s = much better and 120s OK but probably a bit higher works best.  I therefore imaged 4-hours luminance at 180s + preliminary process (to check) and it seems good.  Attached below are 600s L sub (others were worse) and 180s stack + stretch.  

Notwithstanding, I went back to the original 600s L subs and although 90% were saturated some are actually OK + just to repeat, I originally researched other's work on this object B22 and was pursuaded that being a dark nebula the most popular exposures used was 600s or higher made sense. The bottom line is (a) I'm still not sure what's going on but the camera etc seem OK (b) I will be continuing @ 180s and chalking it up to experience + unexplained!

Thanks for the thoughts. 

The Fits header is fine and reflects the correct setting - waiting to hear back from Ivo 🤞 

Thanks Lee, one of those 'astrophotography problems' I expect, i.e. it's staring me in the face but will take forever to sort!  

No I did not have to reinstall any drivers and at first all seemed fine, as after sorting things I completed imaging a narrowband image without (as far as can see as it's not been fully processed yet) any problems.  As I initially said, the RGB subs seem OK imaging B22 and it appears to be only the luminace. 

I've only ever used APT and don't use any other capture software for mono imaging but I'm suspicous of the gain / offset settings, that seem to work a bit diferent with APT v3.90 which I updated to after the crash from v 3.88 and have posted a query on the APT forum for Ivo = watch this space!

Graham   

Yes I do usually use shorter luminance but looking at a number of images of B22 on Astrobin, which being a dark nebula is on the dark side, and most of the better ones seem to use 600 secs or at least 300 secs.

Been playing around this evening even with 180 secs + other settings it's still happening, so not sure what's happening! 

Thanks for your thoughts.

Graham  

I've been working on B22 recently and something funny is happening with the luminance subs.  From the outset they look overexposed i.e. bright white at the time of capture but after stacking + some judicious stretching the detail's there +OK.  Out of the camera (unprocessed) the L subs histogram is heavily skewed to the right but can be corrected as described.  However, last night I got no detail at all with the luminance subs i.e. just a bright white subs which will not stack but the  RGB subs look OK. 

I had a software meltdown (using APT) earlier in January but after reinstalling and sucessfully completing a narrowband image I moved on to B22 when the above Luminance problem occurred.  I'm imaging with a ZWO ASI1600MM camera at Unity (Gain 139, offset 21) and 600 sec luminance + 300 second RGB exposures - been using this for years and not seen this problem before  

Any thoughts about what could be going on here?

I've been wanting to image the truly exciting but faint Simeis 147 AKA the Spaghetti Nebula for some time but the FOV is too much for my equipment and with the lack of good weather here for imaging I've gone instead for a close-up / detail rather than a mosaic, hope you like it?  Even with 12 hours this tricky object is difficult to tease out but I'm still very pleased with the outcome and will be back another year to add to the data.

Graham

Ha 39 x 10mins

OIII 34 x 10 mins

Total Integration = 12 hours 10 min (21st December to 6th January)

Thanks, appreciate the comments, that's very helpful. 

Yes will do, now you mention it there is a slight green cast there, need to go to Specsavers!  

Graham

I'm going to pay for this but starting in October for three months running at or around new moon I had clear skies!  Last time on 6th December for one night only I returned to that seasonal favourite Pleiades with the objective of teasing out more details of those delightful wispy intersetaller clouds through which M45 is passing.  Armed with new Chroma filters acquired last Christmas, better guiding courtesy of the new PHD2 multi-star facility and having shifted to PixInsight for most of my processing over the past 18-months, I'm very pleased with the outcome - certainly it's much better than my previous attempts and, I think, does justice to those exciting clouds.

Using a William Optics GT81 and ZWO 1600MM-Cool I generally like to crop lightly just to tidy up things and only more agressively if it's needed on those smaller objects which this equipment otherwise struggles with.  However, this time I'm wondering if the better image isn't a 60% crop thus producing greater impact - any thoughts?

12 x 300 sec LRGB = 4hours

As the saying goes: you wait ages for a bus then two come along at the same time!  In this case after successfully imaging M31 the Andromeda galaxy which for once coincided with clear skies and the new moon in early October, I was lucky that the next moon cycle in early November also provided good conditions and his time I chose to image M33.  This is a target that hitherto I've struggled with and was therefore very pleased to obtain a good data-set over three nights that included 3-hours of 10-minute Ha exposures.  The result is definitely my best image yet of this attractive target and I am at last happy with the result.

15 x 300 sec LRGB

18 x 600 sec Ha

Total Time = 8-hours

27 minutes ago, Laurieast said:

Is this what you mean, in the middle? £9.98 Month.

https://www.adobe.com/uk/products/photoshop/landpa.html?mv=search&mv=search&sdid=LZ32SYVR&ef_id=CjwKCAiAqIKNBhAIEiwAu_ZLDtpNSoLm5c1HZPD7X3zYVHXk4tlxCf7vsgdkUIkC5Tzb9nTWxpb2ABoClBgQAvD_BwE:G:s&s_kwcid=AL!3085!3!340669891887!e!!g!!photoshop online!1422700211!58647953511&gclid=CjwKCAiAqIKNBhAIEiwAu_ZLDtpNSoLm5c1HZPD7X3zYVHXk4tlxCf7vsgdkUIkC5Tzb9nTWxpb2ABoClBgQAvD_BwE#mini-plans-web-cta-photoshop-card

Ah yes, that looks like it, thanks. 

On 24/11/2021 at 16:36, tooth_dr said:

That is really very good value indeed.

I would agree if I could find it.  The so called "Crerative Cloud" seems to be £49.94 per month or £30.34 today as Black Friday! 

So could somebody please direct me to a link that provides PS for 12 Euros a month - I only waht PS?

Graham 

15 hours ago, malc-c said:

Not sure about the "best" version, but the latest can be found on the CdC web site  4.2.1 has been the current version since November 2019.

Latest build of the Beta version here  but it's beta and not a RC version so what bugs are in it or how stable it is is anyone's guess

Thanks Malcolm, I use 4.2.1 on my main capture laptop but have 4.3 Beta-4167 on another secondary capture laptop. which has been fine.  Following a recent meltdown of my main processing computer I'm slowly reloading software onto a new replacement laptop and couldn't find the beta versions any longer, which I was thinking of using here - not for capture / guiding etc.

Graham  

Can anyone recommend a reliable source for a copy of Photoshop CS3 or above?

Just wondering what the best version of CdC is now and where I can find it to install?

The "stable" version seems to be v4.2.1 but am aware that there are 4.3 beta versions too - would they be better, what's the difference?

Graham