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Old 09-05-2010, 05:08 PM
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SDM#45 first Observation Report 8/5/2010

After 2 full weeks of either cloud, uni commitments or cloud, I finally got a chance to really take the new 12" dob for a spin. Setup and collimation is very easy, no tools needed. One thing I noticed on the scope is that the secondary as seen thru the focuser was slightly de-centered but was busy during the day so had no time to play with it. But I could still get the entire primary reflected in it when I got the optical axis aligned. However defocusing a star the secondary shadow appeared perfectly centered so makes me wonder how much effect a slight mechanical misalignent of a secondary has when the optical axis is perfectly aligned.

I was pleased to note that both the laser and cheshire agree when checking collimation, and collimation stays put throughout the night. No need to re-collimate here! One thing my old dob lacked was cooling fans, plus the mirror was in an unventilated cell so it never cooled down. Now I have 3 fans blowing at the mirror one at the back and two at the front which also stop dew formation while cooling.

Seeing during the night was generally garbage, truly madly deeply abhorrent infact, but transparency otherwise was improving as the night wore on. Seems like we are in jetstream season with the continual "observing above campfire" effect. Some reckon winter provides the best seeing. IMO summer is the weiner in the seeing stakes.

As for the views, this scope has potential given the opportunity to stretch its legs. But I don't live in Florida. Stars at 381x focused into tight airy disks, although smearing in the seeing, but you could see that "snap" underneath the blur! Should have no probs pushing double that mag on certain objects in atleast decent seeing.

I gave the scope it's first real run on some faint galaxies and I must say it performed above and beyond my expectations. Infact I was totally surprised at how well it was raking these fuzzies in!!!

Scope: 12" F4.4 dob
Time: 8pm-12am
Seeing: 2/10
Transparency: 5/5
Dew: no
Temp: 11C


WILD's TRIPLET


MCG-01-30-32

GX, Virgo, RA 11 46 35, Dec -3 51 36, Size= 1.7'x1.1', Mag B= 15.0

2nd of 3. Very faint, although could hold it well at 267x. Increased mag to 381x purely for the purpose of increasing contrast. Lower SFC brightness than MCG-01-30-33 approx 3' ENE.

MCG-01-30-33
GX, Virgo, RA 11 46 45, Dec -3 50 52, Size= 3.0x0.6', Mag B= 14.3

1st of 3. Surprisingly easy to see at 166x. Slightly elongated E-W at 267x and is much brighter than -32 to its WSW.

The 3rd northeastern member was not visible.
----------------

2MASX J11461879-0345353
GX, Virgo, RA 11 46 19, Dec -3 45 36, Size= 0.6'x0.5', Mag B= 16.0

A tiny, high sfc brightness elliptical located only 8' NW of Wild's triplet and forming a "double" with a mag 13.8 star 35" to the north. Extremely faint, SIMBAD lists a blue magnitude of 16.0 Spotted at 381x, could hold it maybe 25% of the time but it winked in and out of visibility as I stared at the field for a good 10 minutes with a black shroud over my head. This galaxy according to its redshift is 663 million light years away!

---------------------

ESO 507-45
GX, Hydra, RA 12 55 36, Dec -26 49 26, Size= 1x0.6', Mag B= 12.8

Bright, large elliptical, 1st of 5 in a group. Elongated N-S, high surface brightness with a condensed core. Forms a nice pair with ESO 507-46 approx 3' NE. A mag 11.9 star lies exactly halfway between the two galaxies.


ESO 507-46
GX, Hydra, RA 12 55 44, Dec -26 48 32, Size= 1.2x0.9', Mag B= 13.9

2nd of 5. Forms a pair with -45 some 3' SW. Smaller with lower sfc brightness than -45 but still quite easy to see at 166x. Slight E-W elongation hinted at at 267x.

2MASX J12554311-2651556
GX, Hydra, RA 12 55 43, Dec -26 51 55 , Mag B= 16.18

Very small, extremely faint galaxy located 5' SE of ESO 507-45. Could hold it about 75% of the time at 267x, with the hood over my head and careful scrutiny of the area. Easy to find halfway between a 15th mag double star to the NW and another mag 12.9 star to the SE.

-------------------------

ABELL 761
This is a rich cluster of galaxies located about 20' S of a mag 6.3 star. A relatively large number of foreground stars aid in pinpointing galaxies here.

ESO 511-26
GX, Hydra, RA 14 18 51, Dec -27 24 35, Size= 0.5'x0.5', Mag B= 14.3

Compact elliptical galaxy located 2' N of a mag 9.4 star. Faint, round and small at 267x. Took a while to see it, but once I was adapted it was quite easy to hold.

MCG-04-34-008
GX, Hydra, RA 14 19 05, Dec -27 24 27, Size= 0.4'x0.4', Mag B= 15.0

Faint, small, round at 381x. Located 4' NE of ESO 511-26. Slightly smaller and fainter than -26, managed to hold it perhaps 75% of the time.

2MASX J14190223-2727348
GX, Hydra, RA 14 19 02, Dec -27 24 34, Mag B= 15.9

Located 4' SE of ESO 511-26. Extremely faint, it took me 10-15 minutes of intent observation with a black hood over my head to catch fleeting glimpses of this galaxy. I was at the eyepiece for a good amount of time to confirm the sighting. Pretty much a non-descript ball of fluff. Finding the location was easy by using a 13.5 mag double star to the SW and a trio of mag ~13-13.8 stars to the NE. A mag 15.2 star lies 1' NW. ANother mag 16.0 star adjoins its southern end, which I suspect I glimpsed a couple of times.

ESO 511-23

GX, Hydra, RA 14 18 27, Dec -27 22 42, Size= 1.4x1.0', Mag B= 13.8

This galaxy appears to be the largest and brightest of the Abell S 761 clan, although is displaced well the the east of the apparent centre. Located about 6' WNE of ESO 511-26. Fairly easy at 166x, but a better view at 267x. Slightly elongated E-W.

ESO 511-21
GX, Hydra, RA 14 18 14, Dec -27 24 55, Size= 0.4x0.3', Mag B= 14.4

Second brightest member of Abell S 761. Located 4' SW of -23 and is slightly fainter and smaller. A mag 10.8 star lies 1.5" E.

Another two galaxies ESO 511-31 and -32 lie on the eastern side of the cluster which look like are within my reach but lost the field and couldn't find my bearings so I had to cut my losses.

---------------------------------------

NGC 5170
GX, Virgo, RA 13 29 49, Dec -17 57 57, Size= 9.24x1.29', Mag V= 10.8

I've been wanting to hunt down this edge on spiral for ages now, but it was somewhat underwhelming. At 166x it appeared as a faint spindle with a fairly bright, condensed core. The dust lane was not seen.

NGC 5746
GX, Virgo, RA 14 44 56, Dec +1 57 19, Size= 7.9x1.7', Mag V= 10.3

Easily found at 41x as a high sfc brightness needle. Located SSE of a mag 8.7 star. A lovely object, IMO superior to NGC 5170. Features a small, buldging core at 166x, with needle like extensions. At 267x a stellaring in the core was hinted at. The eastern edge is harder than the west, a manifestation of the dust lane. A mag 14.9 star lies just offset to the east at the end of the northern extension and another Mag 14.1 star lies along the galaxy's central axis south of the core.

---------------------

Had to pack it in at midnight as cloud started moving in, but satisfied with a great first session.

Last edited by pgc hunter; 09-05-2010 at 05:22 PM.
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Old 09-05-2010, 05:33 PM
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Paddy (Patrick)
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Great to hear that you've had at least a moderate night with your new scope. It sounds a very impressive instrument. I have to say again that you are amazing in your ability to observe faint galaxies with a 12" scope that I would not even try to look for with my 16 and very good skies. Think I just have to keep honing my observing skills!
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Old 09-05-2010, 05:34 PM
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That's great Sab, you really must take that thing to a dark site one day soon.
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Old 10-05-2010, 07:09 AM
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Lismore Bloke (Paul)
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Impressive and well detailed report, well done mate! That scope certainly boxes well above its weight. I'm glad to hear it is exceeding your expectations and look forward to more reports.
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Old 10-05-2010, 07:10 PM
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Thanks guys. It appears this scope goes deeper than the original, perhaps due to the precision offered by the feathertouch focuser and other various factors like active cooling, better collimation and Peter's cleaning job on the mirror

Only thing left to do is finalise alignment of the secondary mirror and get some darned clear skies - and seeing! Saturday looks good, might try for Serfert's Sexytet and a few other's from Les's column in the recent S&T.
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Old 10-05-2010, 08:20 PM
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Hi PGC & All,

Very glad to hear it all worked out, not that it was ever really in doubt Peter (SDM) does a top job with his gear. Good to hear you are happy with it too. Excellent report, especially Wild's triplet. As can be plainly seen from the DSS plate, these are very faint galaxies indeed.

Hope you do well with the Hicksons! As you can see in my last report, I saw a few more Hicksons too -- love 'em!

Best,

Les D
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Old 11-05-2010, 09:16 AM
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Quote:
Originally Posted by ngcles View Post
Hi PGC & All,

Very glad to hear it all worked out, not that it was ever really in doubt Peter (SDM) does a top job with his gear. Good to hear you are happy with it too. Excellent report, especially Wild's triplet. As can be plainly seen from the DSS plate, these are very faint galaxies indeed.

Hope you do well with the Hicksons! As you can see in my last report, I saw a few more Hicksons too -- love 'em!

Best,

Les D
Hi Les I actually found the brightest member of Wild's Triplet to be quite "easy", but the second member was far more difficult. I haven't found any obs reports on Wild's Triplet. Any out there? Gonna go after Seyferts Sextet and Abell 2151 on the weekend seeing as it's going to be clear on Saturday Might try for The Box aswell if I can get out early enough.
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Old 11-05-2010, 09:26 PM
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Quote:
Originally Posted by pgc hunter View Post
One thing I noticed on the scope is that the secondary as seen thru the focuser was slightly de-centered but was busy during the day so had no time to play with it.
Just make sure that Peter hasn't off-set it on purpose. I don't bother with mine, but the text book says you should...

http://www.asnsw.com/info/offsetcalc.asp
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Old 11-05-2010, 09:39 PM
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Quote:
Originally Posted by AstroJunk View Post
Just make sure that Peter hasn't off-set it on purpose. I don't bother with mine, but the text book says you should...

http://www.asnsw.com/info/offsetcalc.asp
Mine's actually offcenter towards the front of the tube, I asked Peter about it and all I have to do is move it towards the primary using the collimation knobs. When it's centered in the sight tube. When you've made the secondary concentric with the bottom of the sight tube, that automatically incorperates the offset.
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