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NGC281 Ha with the Skywatcher Mak-Newt 190mm

SteveL

By SteveL
in Imaging - Deep Sky

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SteveL

SteveL

Posted
Posted

Finally, after what seems like an incredibly long "new kit" induced period of clouds, the skies cleared last night. Seeing was OK, transparency was borderline rubbish, and the moon just made things worse

flo-swmn-06-onmount.jpg

But... there were stars, and plenty of them. I was hoping the skies would stay clear all night so I could go for an RGB target, but alas the clouds rolled in at about 2.15am. The image is a bit noisey due to the transparency and the moon glow, but I`m happy with this as a first light with the Mak-Newt

After running PoleAlignMax to get a really good alignment, here is the result:

OTA: Skywatcher 190mm F/5.3 Maksutov-Newtonian Astrograph

Guiding: Skywatcher ED80 + DSI-C + PHD

Imaging: QHY8 + MaximDL, 20×600s, Astronomik 13nm Ha

Stacked: DeepSkyStacker

Post Process: ImagesPlus + PSCS2 + Noel Carboni’s AstroTools

(Note: The slightly elongated stars that are visible in the larger version are due to the strong wind that was moving the OTA and mount around a bit, and is not any kind of optical flaw with the OTA or camera)

(Click on image for larger version)

ngc281_ha_20081107_800.jpg

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Tim

Tim

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Its certainly captured some nice detail on the dark areas of the nebula. Is the image cropped Steve? If so, how flat is flat? The stars appear ever so slightly stretched, but is that the guiding or a result of the optics would you say, the lousy transparency, or even just the stacking?

What about the need for a dewshield or band on the front? It was dripping wet here with dew for the short cloud free period.

At any rate, you must be encouraged by that result, cant wait to see some RGB piccies from it!

TJ

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SteveL

SteveL

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The star elongation (all in one direction) is due to the gusty wind we had last night, the guiding was working really hard to keepon target, which also meant no dew shield because that would have just made things even worse. I did have my dew strip running, and it REALLY hammered my battery packs. As its a partially open tube design (with vents around the outside of the corrector/miniscus), am wondering if any heat build up was just just getting blown away.

It is a crop, due to some odd gradient in the final image. CCD Inspector shows a VERY flat field from a raw full size FITs file.

flo-swmn-07-ccdinspector01.jpg

flo-swmn-07-ccdinspector02.jpg

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Tim

Tim

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Thanks Steve. I think its official now, you have the National Collection of Telescopes & Astronomy Software.

Ooh, how was the focusser btw? Is it the standard one or did you upgrade? I've never seen the dark lanes captured so distinctly on the Pacman.

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FLO

FLO

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The star elongation (all in one direction) is due to the gusty wind we had last night, the guiding was working really hard to keepon target, which also meant no dew shield because that would have just made things even worse.

Thank-you for preserving against the odds Steve :thumbright:

CCD Inspector shows a VERY flat field from a raw full size FITs file.

flo-swmn-07-ccdinspector02.jpg

Fantastic! :cheers:

I've always wanted a Mak Newt so its great to hear that it can deliver the goods :D

Can't wait to see what you produce on a good night!

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SteveL

SteveL

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As this is my first "Newt" of ay kind (hey, its a newt with a corrector!), I had to learn a few things quickly... like I`ll remember next time to put the OTA so right angled finder is on the OUTSIDE <sigh>

The focuser is the standard synta 1 speed focuser, with the usual thumb screws to adjust the friction. Oddly, I was under the impression that I`d be able to gain focus "as is", but for the QHY8, I had to use the extension tube to get it to focus.

(Note the finder on the... err... wrong side :help: )

flo-swmn-02-focuser.jpg

The other thing I found odd was that despite being primarily aimed at the imagers, it appears that the only way to attached the imaging kit is via the 2" eyepiece hole. Id` like to see a T-Thread or a SCT thread on the end of the draw tube.

If the OTA was mine (and from last night's sessions, I`m tempted by this scope), I`d upgrade and get a Moonlite 1:10 focuser for it (Note: Unsure if the moonlites fits, so dont assume they do!). I found the standard focuser a bit too coarse to snap into focus easily. It works fine, its just that I`m spolied with my C8 being electric focuser, so maybe I just need some practise doing the whole "manual focus" thing :lol:

I would also change the right angle finder for a Telrad or an RDF of some sort, but again thats just personal preference.

Steve - I`ll continue to preserve (and also persevere), whichever allows me to keep this scope the longest! :D

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FLO

FLO

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If the OTA was mine (and from last night's sessions, I`m tempted by this scope), I`d upgrade and get a Moonlite 1:10 focuser for it (Note: Unsure if the moonlites fits, so dont assume they do!).

I dare-say Ron at Moonlite is already working on an installation kit - we have pre-ordered some in anticipation.

Steve - I`ll continue to preserve (and also persevere), whichever allows me to keep this scope the longest! :D

The season is well and truly upon us Steve, we are (sadly) too busy to play with yet another new scope! Feel free to keep it til next year :help:

Besides, you are better able than us to give it a thorough testing and FLO's gallery could do with some new images :lol:

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SteveL

SteveL

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While you have it can you meausre the OD of the front ot the OTA and the diameter of the central obstruction please...

As requested, and all measurements approximate-ish

Outside Diameter: 240mm (8" dew band fitted perfectly)

Central Obstruction: The cap on the outside of the corrector/miniscus is 50mm diamter, but the secondary mirror appears to be slightly larger that this.

OTA length: 935mm

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Whippy

Whippy

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Just looking at that pic of the focuser, I'm wondering if that's the same unit as the new explorer crayfords and AFAIK, the new SW autofocusers include a bracket for those models do they not? If that's the case then there'd be no need for a dual speed Moonlite to get accurate focus.

Nice result for a first light, that is a VERY flat field!

Tony..

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