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vineyard

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Posts posted by vineyard

    More microscope eyepieces reworked!

    in Discussions - Eyepieces

    Posted

    +1 for microscope EPs.  Have been using Zeiss E-PL 10x20 for years in the 25mm range (no need for Panoptics) - amazing.

    For barrel adjustment to 1.25" in addition to the tips above, a vendor called MadridSky on eBay also sells machined adapters.  V good.

    An off the beaten path microscope option is to use Nikon Optiphot/Labophot heads.  It's like a diagonal with a barlow and a BV in one.  Again v v good optics given the provenance - I'd say pretty much on a par w Zeiss.  Those EPs can be had in 10x (25mm equiv) and 15x (c 17mm fl equiv). The FOV will surprise you.  Only wrinkle is that they are narrow barrel (maybe 23mm), and so need different adapters if you want to use them in traditional astro BVs or diagonals (these adapters are also sold by Samuel at MadridSky - I have no affiliation with him).  Ridiculously cheap EPs for the price you can get them on eBay.  (I can't claim credit for discovering them - a discerning CN'er pointed me towards them so am paying it forward here).

     

    • Like 1

    Mono really is faster

    in Getting Started With Imaging

    Posted

    15 minutes ago, edarter said:

    But doesn't that mean that the CLS is effectively doing nothing? 

    If the Astronomik curves are correct, the CLS is cutting off the long-pass.  The Astronomik UHC seems to be somewhat akin to a long-pass filter above 630nm so the CLS would cut that off at about 700nm.  (The Baader UHC curve seems to have a shut off in it unlike the Astronomik UHC, at least going by Semrock curves: https://searchlight.semrock.com/?sid=a08a1af9-84ee-49d2-959d-153d7e7c0eb8#)

    Mono really is faster

    in Getting Started With Imaging

    Posted

    Thanks @vlaiv - nuanced explanations such as yours is part of why SGL is so rich to learn via.

    From my clumsily phrased perspective, I was just really surprised at the difference in the two images.  For my crude mental model, in the OSC+double stack, all the 4 Bayer arrayed pixels are being used for 4.5-5h yet so much of the structure still doesn't come close to emerging - whereas in the OSC+NB (which to my mind means akin to a mono camera with 1/4 of the pixels, albeit with interpolation between the pixels which a pure mono wouldn't need to do) one night gave so much richer data.  Maybe "NB is faster" is a better formulation for what has surprised me.

    I hear you on the set-up & flats - people's mileage will vary but for me <2h in one night vs 4 nights to get 4-5h is much more convenient, especially with that much difference in data.  (I'll admit I'm lazy and if I haven't messed with the setup & no big changes have happened wrt dust bunnies, I just use the same flats for a few nights - I suppose slight focus changes night-to-night should mean I should take new flats).

    Cheers!

    Mono really is faster

    in Getting Started With Imaging

    Posted

    I think it would depend on which filters you stack @edarter & @tomato.  If I had 2 proper NB filters, I wouldn't stack them b/c they'll be working on different parts of the spectrum as you say.

    I can't remember where I first read of this double-stacking but I think it was in some obscure CN thread.  Based on the logic described therein, I double-stacked an Astronomik UHC & CLSCCD filter.  I've pasted their respective band-passes below - I think b/c they work on v similar parts of the spectrum (as you surmised @ollypenrice) but w slightly tighter passes in the UHC, the combined effect is a bit closer to a dual-band like L-Enhance (still not as tight as that & nowhere near as tight as an L-Extreme).

    The interesting thing is that in solar, double-stacking HA etalons does tighten the bandpass but perhaps that's because of a different physics being used wrt the filtration mechanism?

    Thanks too for that image @The Lazy Astronomer - v v helpful.  I'll try and do a Pixelmath comarison later, but at quick glance I think there's more finer detail in that than even w the OSC+NB, which would be another validation of mono?

    image.png.87738dce91bcbda33b74b6595d2699ad.pngastronomik_uhc_trans.png

    Mono really is faster

    in Getting Started With Imaging

    Posted

    While I save for a fuller frame camera, the eternal debate of mono vs OSC (+dual band filters) wages on in my head.  And a point often made is that mono is actually faster not slower.  I think I just saw an example of this.

    Two images below - the colour is about 4.5-5h of OSC over 4 nights last autumn (w dual-stacked filters to synthesise a dual-band) on NGC 6888.  The red one is only 1h48from last night via a 6nm HA filter and the same camera 294MCPro on the same target.

    The difference in data gathered is shocking.  Clearly a tighter NB filter will be helping (vs synthetic dual-band), but this is as a semi-mono w c 60% less capture time than the OSC - so I'd imagine a proper mono would have captured even more data?  And btw this is on full moon night at a time of year when astro dark doesn't exist (even if the moon wasn't out).

    Mono really is faster!

    NGC6888_TV102rf_uhc_clsccd_ASI294MCP_session_1_session_2_session_3_session_4_DBE.jpg

    NGC6888_6nmHA_1h48_ABE.jpg

    • Like 3

    The Blue Horse

    in Imaging - Deep Sky

    Posted

    20 hours ago, peter shah said:

      The 'tilt' is actually an artefact of the stacking procedure caused by the objects altitude....I am looking into it to see if I can get better registration by tweaking the alignment settings. The stars are actually pretty round from corner to corner in the single frames. This object is very low down and is effected by atmospheric refraction. The frames were captured starting from at around 18 degrees and I think peaked at around 29. 

    Yes I'd noticed that those shapes only seemed to be on the bottom edge not the top, hence my curiosity.  Interesting re it being an altitude-related stacking artefact.  I'm afraid I don't understand the subtleties of stacking algorithms anywhere near remotely but intuitively yes I can see how higher refraction lower down while the image registers based on stars higher up could do that.  It's almost like there's a need for adaptive registration for stacking purposes.

    Looking fwd to seeing the fuller project.  And cracking vistas from the obs.

    The Blue Horse

    in Imaging - Deep Sky

    Posted · Edited by vineyard

    That's stunning.  Is there any justification left for mono when OSC delivers that?

    Couldn't help pixel peeping (it's that good an image!) and is there some v v slight tilt (there seem to be some trails towards the bottom edge)?  (That's not a criticism btw - I'd be over the moon w an image like that - more curiosity)

    • Like 1

    15 inch dob and 8 inch with night vision

    in EEVA - Reports

    Posted

    On 06/06/2022 at 20:37, TBRHussaR said:

    Afocal - so no eyepiece used...

    Do you mean prime focus (I think afocal involves an EP)?  Great images of the most recent 2 galaxies too.  You're definitely motivating me to take the 7"+NV on a galaxy hunt :)  What f-ratio are those galaxy observations running at?  (If its a Celestron 8" with NV at prime focus then that suggests f/10?)  Thanks!

    • Like 1

    15 inch dob and 8 inch with night vision

    in EEVA - Reports

    Posted

    I'd echo the step change that NV makes - I use it in Bortle 8/9 skies with a 7" Mak, 5" Mak and 3" frac.  It's a complete game-changer for visual.  I haven't had a chance to run it on any galaxies yet (mostly globs & some nebulae) so your report on M51 w an 8" is v encouraging.  Can I ask what f/ratios you were effectively running your NV at (ie, the native f-ratio of your scope & if you were doing this afocally, which EP you were using?)?

    Thanks

    • Like 1

    M101 - 9h44

    in Imaging - Deep Sky

    Posted

    Thanks Steve, that's v kind.  IKWYM about what is out there.  I actually hadn't appreciated how many other objects are out there even just around M101 - have started capturing some data w the newer wider-field imaging setup & there's quite a few other things up there even in just that bit of sky.  To think there's probably creatures out there looking at/towards us wondering the same thing.  Or else it's all just a simulation😂

    M101 - 9h44

    in Imaging - Deep Sky

    Posted

    Am in the process of changing imaging scope, so just cleaning out data captured with the old setup.  Here's 9h44 of M101 roughly equally split between CLSCCD & HA filters.  This is a crop of about the central 1//3-1/2 (from memory) of the aggregate image taken w an ASI294MCPro & a TV102iis w a 0.79 reducer-flattener.  Rescaled jpg for size.

    Cheers.

    M101_9h44_CLSCCD_6nmHA_gimp_wm_rescaled.jpg

    • Like 6
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