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perfrej

First light TS130 w Riccardi - M81 (oh, that %¤*#" moon!)

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Last Saturday the clouds parted for a few hours around lunch-time. This gave me the chance to hook up my new TS 130mm APO with Riccardi reducer on the GM1000HPS on the balcony. We've had a constant cloud cover for months, so this was a welcome opportunity!

Sunday night the skies cleared again for about half an hour and I managed to get a vcurve run done, proving the focuser worked OK. Last night, which is choir practice for me, always, was forecast to have clear skies all through Tuesday! Wow!

I took the cover off the rig in the morning, started all relevant software and drove off for a short work session that was to last to 16:40. At 17:00 I sat down at a sushi place in Stockholm, opened the iPad and started a model run so that I would have decent tracking. After that I enabled CCD Autopilot and went to practice.

Came home around 21:30 and had the first run of 12 L and ten each of R, G and B. Focus looked so-so, prompting me to sit down and run another set of vcurves with backlash compensation enabled. That did it. Re-started CCD Autopilot with the same run and a set of sky flats for the morning hours and went to bed.

This morning I processed it. Moon was up, obviously, I had some specks on the L filter and 17 satellite trails spread out over the run ;)

So, a quick and dirty process in PI resulted in the image below. Details:

Mount

10Micron GM1000HPS on balcony steel pier

Camera

SBIG ST-8300M, SX USB wheel, Baader 36mm unmounted filters

Scope

TS 130APO with Riccardi reducer, effective FL 762mm at f/5.2, stock focuser

Control

CCD Autopilot, FocusMax, MaximDL, Pinpoint 5

Subs (none lost, all unguided)

24 x 5 min G (removed a few with too high background noise)

20 x 5 min B (lost a few to dawn light)

30 x 5 min R (full set)

36 x 5 min L (full set)

Flats and BIAS applied.

Full image at 100% at http://filer.frejvall.se/2014-02-17_M81_130_LRGB_PI.jpg

2014-02-17_M81_130_LRGB_PI_800.jpg

Crop of galaxies:

2014-02-17_M81_130_LRGB_PI_Crop_800.jpg

It appears that the scope works. Slight focuser slop, nice and clear, no artifacts, very flat field. Seems to be a really good scope!

All the best,

Per

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Looking good Per,

I guess you have answered the "how are you getting on with the TS130?" question I forgot to ask you earlier!

All the best

Nick

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Looks very promising. Some noise due to moonlight, obviously. Hope you get some clear skies when the moon has buzzed off. You can still make out SN2014J in M82. Clearly fainter than its maximum by now.

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Thanks, folks.

Yes, there is noise but it doesn't really bother me. I could sweep it but it is just a test image and won't be put to use. I will try to add some Ha, perhaps ;)

/per

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Nice images. Some nice faint dust starting to appear.

it might be my screen settings but there appears to be dark spots in places. It looks like a problem with the flats?

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Ohhhh blimey... get the cleaning tissues and rocket blower out - thats a filthy camera  young man!  :D

But the you main goal of a flat field has been achieved superbly. Hmmmm.... 762mm at f5? I feel that would bin quite well on the 8300, especially if you need to put up a mosaic quickly.

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Yes, there are specks in the Lum subs. I almost got them out with sigma rejection. I'll clean the [removed word] next time I bring it down, but for now I'll figure out a way to fix it in processing.

Yes, 762 at f/5.2. It is reasonably fast and does the job. I do not bin myslef so I wouldn't really have a feel for what kind of gain there is to have.

/per

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Nice one Per, for those humble newbies like myself please can you explain where on the image makes you decide that you have focuser slop.

Regards

GG 

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perfrej, on 18 Feb 2014 - 09:42 AM, said:

Yes, 762 at f/5.2. It is reasonably fast and does the job. I do not bin myslef so I wouldn't really have a feel for what kind of gain there is to have.

/per

Not sure on your 8300, but I tested the Atik and it came out as a 2.23x gain. That was done by taking a series of binned and unbinned images, them measuring the ADU values of a few stars in each image to get the gain value.

Normally, I wouldnt bin either - but the UK weather has been forcing the issue, for the last couple of months its been a case of treating clear sky as if its for one night only and get as much signal out of it as possible.

Edited by Uranium235

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Hi per, thanks for the review. I have been considering buying the TS 100/f5.8 or 130/5.2. Looking at your pics there are two things that might concern me:

a. brighter stars seem a little diamond shaped. I get this with my R200SS, but this is a Newtonian! Is there anything causing diffraction in your image chain?

b. some noticeable red halos - possible CA?

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The slop is evident from a numbe facts.

Firstly, the modeling of the mount takes into account predictable flexure and the net results in terms of expected RMS tracking error tell me that there is slop. Secondly, I can move the dang thing by hand and it will wiggle a bit... Thirdly, and analysis in CCD Inspector proves this y showing the top right corner having worse FWHM than the rest of the image. It is by no means much, but still... It is not a dirt cheap telescope so one expects a little more.

All in all, it is very good, though!

Here's the result from CCD Inspector:

post-9361-0-27735500-1392718074_thumb.pn

All the best,

Per

Edited by perfrej

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Well done that man, it makes all the hassle worthwhile when the end product is that good :smiley:

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Thank you for the explanation, looks like a good scope even though I have heard lots of horror stories with the quality of TS scopes.

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Fantastic image Per with good detail and lovely colouring! :smiley:  A friend has a couple of TS scopes and speaks very highly of them, worth a good look I would say.

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Thanks!

Yes, the optics are really good, but I am a little puzzled over the general checkout procedures at TS. I returned a brand new 102 because the adapter to the flattener reached the optics retainer ring before the flange made contact. Besides that, the focuser wasn't even screwed together completely with lots of loose parts.

This one had the same problem with the adapter not reaching the flange in the adapter. I measured it screwed all the way in and there was almost 0.1 mm difference between two opposite sides. No way that reducer ends up straight in the optical path.

Here's the adapter:

post-9361-0-50353200-1392743942.jpg

And here is the adapter screwed as far in as it went in the reducer. No contact with the flange, as is evident:

post-9361-0-13720900-1392743933_thumb.jp

I had to grind off 2.5 mm off the left side of the adapter as seen in the first picture.

In a sense it is like an NEQ6; you have to tweak it before it delivers. I, for one, can handle that, but in my view the TS scopes are not for the folks with three non-opposing thumbs in each hand or for the faint of heart ;)

/per

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Wow, surely not just me who sees flaws in star shapes and CA there? I have been imaging for nearly 10 years and that CA looks as bad as achromat Takumar SMC lenses I have used (not a criticism of the imager I hasten to add). Any thoughts Per?

Edited by Dangerous-Dave

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Great image plenty of detail in the dust lanes of M81

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