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gorann

NGC 5985, 5982 & 5981 - a triplet in Draco

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Posted (edited)

Did some more galaxy hunting over the last two nights with the Esprit 150 on the Mesu 200. Here are 5 hours spent on this triplet using the ASI071 (OSC) (62 x 5 min, gain 200, offset 30, -15°C). The moon was out but on the other side of the sky so it did not cause any gradients. However, seeing was not the best.

I post both the full frame and a rotated crop. I think I am now getting to the lower size limit of what can be successfully imaged with a 6" refractor with a 1050 mm FL, at least with this pixel size (4.78 um). In any case we are also rapidly running out of astrodarkness up here.

 

 

20190411+12NGC5985 PS39smallSign.jpg

 

20190411+12NGC5985 PS42smallSign.jpg

Edited by gorann
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A group I have not seen before beautifully done as far as I can see, prefer the cropp if I'm honest, these must be very small, maybe my Meade 12 inch SC would be a tad better though much more difficult to guide I imagine, since it was evicted from the obsey it has not been used.

Alan

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8 minutes ago, alan potts said:

A group I have not seen before beautifully done as far as I can see, prefer the cropp if I'm honest, these must be very small, maybe my Meade 12 inch SC would be a tad better though much more difficult to guide I imagine, since it was evicted from the obsey it has not been used.

Alan

Thanks a lot Alan! Yes, next galaxy season I may use my EdgheHD 11" if seeing and guiding are collaborating.

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10 minutes ago, Grimbles said:

Excellent image, I really like that FOV.

Thanks Grimbles, much appreciated!

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13 minutes ago, gorann said:

Thanks a lot Alan! Yes, next galaxy season I may use my EdgheHD 11" if seeing and guiding are collaborating.

My very first efforts were with the Meade SC on it's fork, just 20 or 30 seconds, I got some images but nothing compared to yours. As bad as they were it put a smile on my face, 3048mm is a bit of a tough spot to start image work at, 805mm is much easier. I have the reducers for the Meade and will sometime in the next 18months get a bigger mount, maybe an EQ8 or CEM 120. I have all the mounting gear for the Meade so must try it one day. I imagine the Edge HD is much the same F/L wise, ie about 3 times the size of the Espirit 150.

Alan

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26 minutes ago, alan potts said:

My very first efforts were with the Meade SC on it's fork, just 20 or 30 seconds, I got some images but nothing compared to yours. As bad as they were it put a smile on my face, 3048mm is a bit of a tough spot to start image work at, 805mm is much easier. I have the reducers for the Meade and will sometime in the next 18months get a bigger mount, maybe an EQ8 or CEM 120. I have all the mounting gear for the Meade so must try it one day. I imagine the Edge HD is much the same F/L wise, ie about 3 times the size of the Espirit 150.

Alan

Yes, FL will be a challenge. With the dedicated 0.7x reducer I am down to about 2 m with the Edge HD11", so about twice that of the Esprit 150. With the Mesu mount on a clear night it should really not be a problem.

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Posted (edited)

Very nice, Goran

Yes, 1050 mm is a bit on the short side for the vast majority of galaxies - I reckon a minimum of 2 metres as I now use.  I used to have a 12" Meade f10, so a little over 3 metres.  That nicely framed galaxies on a medium size imaging chip, but unfortunately my seeing here was rarely good enough for finer detail.  As far as guiding goes, for several years now I have used 'Active Optics' units, the AO8 for my SBIG camera, and now the Starlight Xpress unit with my QSI 683, guided with a Lodestar X2.  So if one has a Lodestar or similar Starlight Xpress guide camera, I can 100% recommend the SX unit.  Not cheap I know, but I wouldn't be without mine - it really does improve the accuracy of the guiding.  I say Lodestar because then the SX driver is installed - I don't know if their AO unit can be used with other makes of guide cameras.

Added a little later.  I see you used the ASI071  which I believe has an APS-C sized sensor.  So do you use a field flattener with it?

Cheers,

Peter

Edited by petevasey
Added text

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Posted (edited)

Thanks Peter! AO is well worth looking into particularly since I am in an area with a dark sky (had a few recent nights with SQM 21.6) but often rather bad seeing.

Now I have to find a target for tonight. It is getting lighter (5 hours of AP is max now) and the moon is starting to intrude. This may be one of the last nights until late August so, anyone, suggestions of rarely imaged galaxies are most welcome (or I may have to go for Leo Triplets or M81-82?)

Edited by gorann

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After looking at the image again it all felt a bit too reddish, so I moved it a bit towards blue (using curves in PS)

20190411+12NGC5985 PS44smallSign.jpg

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1 hour ago, peter shah said:

Beautiful set of images Goran....great star colour  :thumbsup:

Thanks a lot Peter, much appreciated!

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Hi. Excellent -not reduced to death!- natural stars.

Great shot.

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38 minutes ago, alacant said:

Hi. Excellent -not reduced to death!- natural stars.

Great shot.

Thanks! Yes easy does it in processing.

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