February 2009 - Utah-Astronomy - mailman.xmission.com

M57 +73PSW-3
by daniel turner 27 Mar '13

27 Mar '13

Mark your calendar for early evening May 7. Their will be a close encounter between the Ring nebula and periodic comet 73P. The comet will be close to earth so its exact position in the sky will depend stongly on your location on the globe. Go to spaceweather.com and use the link at the bottom of the page for "Observable Comets". 73p is in the list and includes orbital elements and a link for daily ephemerides. DT __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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Patrick's Schmidt camera
by Jerry Foote 10 Mar '09

10 Mar '09

Hi Patrick, It's time to give up your addiction to acetic acid. Check this out: http://www.ast.cam.ac.uk/~ipswich/Telescope_making/Schmidt_CCD/Schmidt_CCD.h tm Jerry Foote ScopeCraft, Inc. 4175 E. Red Cliffs Dr. Kanab, UT 84741 435-899-1255 jfoote(a)scopecraft.com

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Patrick's 2nd HH data (long post)
by Jim Gibson 09 Mar '09

09 Mar '09

I gave Patrick’s 2nd batch of the HorseHead data a shot. http://www.slas.us/gallery2/main.php?g2_itemId=1173 ONLY READ ON IF you are interested in MaxIM DL and PhotoShop image processing. I will try to give full disclosure here. First of all, obviously Tyler is the target; in other words he has set the standard. So I downloaded a copy of his HH image processed data as contained in Patrick’s (his data) gallery site: http://www.slas.us/gallery2/main.php?g2_itemId=1025 . I used that image as a model just to look at and see if I could come close to it with Patrick’s 2nd batch of data. I used Joe’s way of processing as follows. 1 - I took each of the clear photos and subtracted the dark from it. 2 - Then I used a "remove bad pixel" feature of MaxIm DL to get rid of bad pixels, some of which were in more than one of the frames. The feature keeps a map of bad pixels so you can apply it to other views from the same session. 3 - Next I picked out the clear that seemed to show the best range and used an "equalize screen stretch" button to make all the clears about the same. 4 - I combined them using various methods to see which was the best. I think the best one turned out to be taking a medium of the images. 5 - I did the same sort of thing for the colors, except that one -- I think it was green -- had only one image so I didn't combine it with another green. 6 - Finally I Color Combined LRBG without playing with curves because it seemed about right as it was. My last operation was to adjust the brightness and contrast with MaxIm DL (Max). <End Joe’s Way> I did 3 additional things in Max before saving the image as a TIFF. If the image is saved in Max at that point and brought into PhotoShop (PS) then you have a black image. The image has to be stretched using curves and levels to see anything because of the way Max and PS approach things differently. So, I used Max to stretch the data first because when comparing the two I felt Max did a better job for the initial stretch than PS. Here is what I did. (I am going into detail because this is a learning thing. Also if there is a better way, maybe Tyler can set us straight.) 1 – In the Screen Stretch box I manually stretched the right had carrot as far to the right as I could without clipping any star data. 2 – In Max I selected menu item Process > Stretch and set these parameters Linear Only, Screen Stretch, and 16-bit and clicked OK. 3 – Again in Max I selected menu item Process > Stretch again and set these parameters Gamma (0.5), Max Pixel, and 16-bit and clicked OK. Then I saved the image as a TIFF for Photoshop. >From here on it gets fuzzy because I did a lot of playing around. In PS the image will still be a little dark. So Using Tyler’s image as a guide I used curves and levels in the RGB to bring up the contrast and brightness in moderate steps keeping an eye on the histogram to be sure I wasn’t clipping data. When you see the combing effect in the histogram you know you are stretching the data pretty far. The noise will also increase as you boost the brightness and contrast. When I got the image to about what Tyler’s brightness looked like then I went into the Blue level and just stretched it a bit to give the background a bit more of a blue hue than straight black. Now I checked Tyler’s image and noticed his stars were smaller than mine. Size matters, so I created a mask for just the big stars by : 1. Creating a duplicate image and doing a Hi-pass filter with threshold = 1 2. Did a Gaussian blur with threshold = 1 3. Went into Image > Adjust > Threshold and played with the slider till mostly the big stars were left. I cloned out anything I didn’t want till I had the mask I wanted. 4. Then I did a menu Select >All, then Edit > Copy. 5. In the original image I created a duplicate layer of the original image, then went to the channels tab and created a new channel. I pasted the mask into the new color channel. I then clicked on the eye of the RGB channel to reveal the image, then went back to the adjustment layer and clicked on it. From there I went to the menu items. I clicked on Select > Load Selection and lo-and-behold all my big stars were selected. 6. With the big stars selected I enlarged the image to get a closer look at the selection. The selection wasn’t big enough so I went to menu item Select > Mofiy > Expand and increased the size of the selection by 1 pixel. 7. Satisfied with the selection I went to menu Filter > Other > Minimum and it shrank the stars. If you look at some of the stars you will see a halo around them. I don’t have this process down perfect yet. I felt my image was looking pretty good at this point but Tyler’s image was much smoother. Being this close I had to go all the way, so I went out on the web and bought NeatImage as a plug-in to PS. Once I applied NeatImage I felt it smoothed out the noise very well and can give Tyler a run for his money. That may have sounded boastful but it was meant as a thank you for helping us overcome the huge learning curve in image processing. And no less thanks to Patrick and Joe and all of you who have added your input to help us fledglings along. Jim

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Re: [Utah-astronomy] Lulin -- obs report
by Canopus56 08 Mar '09

08 Mar '09

http://antwrp.gsfc.nasa.gov/apod/ap090225.html Yep, Lulin's definitely a useless cur. It's only worth looking at those once-in-40 year comets like McNaught or what's that other 40 year old comet you guys are always calling the "big one"? -:) Kurt

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Bogdan refractor
by Patrick Wiggins 05 Mar '09

05 Mar '09

Bruce Grim, Roger Butz and I have been working to get the Bogdan refractor ready for the upcoming SPOC season. A few days ago Roger decided the scope's brass tailpiece needed to be polished (it had not been polished in a very long time). So polish it he did and here he is with the result: http://users.wirelessbeehive.com/~paw/temp/roger01.jpg Thanks Roger, patrick

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Re: [Utah-astronomy] Tribune Astronomy Blog posts and a plea
by Canopus56 03 Mar '09

03 Mar '09

Sheena, > Well, it's that time of year. The editors at the paper are going > through and eliminating blogs that don't have high readership or > reader interaction (ie comments). It's unclear to me what we need to do to generate a click record for your management's stat tracking on your blog, The Final Frontier. Is it: a) Posting comments b) Subscribing to the RSS feed c) Other? I generally hit the rss subscribe, read it regularly and leave it at that. Is the pass/fail test for the Trib editors posting comments? - Thanks, Kurt http://blogs.sltrib.com/frontier/

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HH 2x2
by Patrick Wiggins 01 Mar '09

01 Mar '09

Here's the latest kit (probably the last for a while). http://users.wirelessbeehive.com/~paw/temp/HH2X2.ZIP Again of the Horsehead but this time binned 2x2 (less sensitive that 3x3 but finer grain). All are 2 minute, guided exposures. 26 MB. Contains: 10-Luminance 4-Red 4-Green 6-Blue 1-Dark 1-Flat for each color and the luminance This is what I was able to make from it: http://users.wirelessbeehive.com/~paw/temp/HH2X2C.JPG More yellow stars. Grumble. Considering others were able to get whiter stars using my 3x3 data and I keep getting yellow I'm guessing I'm missing something. Tyler, a few of us were talking last evening and agreed it would be fun to have you to lunch/dinner one day so we could get some extra instruction. If that sounds like something you'd like to do please let me know when you're going to be in SLC and we'll see about putting something together. patrick the yellow

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Venus/Moon
by stormcrow60＠xmission.com 28 Feb '09

28 Feb '09

That was one of the more spectacular conjunctions I have seen in quite a long time. It reminded me of the Turkish flag. Is it any wonder they used this symbol for their national identity? Truly an awe-inspiring event. Jon

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The Winter Spectral G
by Canopus56 28 Feb '09

28 Feb '09

With Orion transiting it is good time to use the "Spectral G" for a little after work binocular education sessions. The Spectral G is an easily seen series of bright stars that run through the spectral main sequence - OBAFGKM. It has nearly the same stars as the Winter G asterism. http://users.erols.com/njastro/faas/pages/winter-g.htm The Forum for Amateur AstroSpectroscopy (FAAS) has a chart showing the sequence: http://users.erols.com/njastro/faas/pages/winterg3.htm The sequence is: O Alnitak B Rigel, Alnilam, Bellatrix A Castor F Procyon G Capella K Pollux, Aldebraran M Betelgeuse This spectral sequence is an easily done after work, outside the warm kitchen door type review. To the FAAS list, I would add the "C" carbon class stars, which require laptop planetarium charting and probably GOTO locating under light polluted skies: BL Ori SAO152427 4.7v Red carbon J062528+144319 W CMa SAO152427 6.7v carbon star J070803-115522 X Cnc SAO98230 6.2v Stellar ruby J085523+171353 Clear Skies - Kurt ================== This post is a continuation of my posts that concerning on my current observing focus: "after-work urban-astronomy". Urban astronomy focuses on using easily set up GOTO scopes across for seasons to view astronomical objects from urban light-polluted skies. As opposed to deep sky object emphasis, urban astronomy concerns bright objects visible with small apetures e.g. - open clusters, double stars, planetary and solar system objects. Having family, friend and work obligations like the rest of you, I will try to limit referenced targets to those observable prior to local midnight.

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Moon/Venus
by Chuck Hards 28 Feb '09

28 Feb '09

That was a very close pairing tonight; very beautiful and soul-stirring. I watched Venus set behind a distant roof-line. It was interesting in that it didn't wink-out immediately, like a star does during a lunar occultation. It took a couple of seconds to dim and finally disappear; proof that it subtends a measurable angle and not a point source. As Venus approaches superior conjunction, it will swell to a minute of arc in apparent diameter- this is large enough for sharp-eyed individuals to detect the crescent shape. Use a neutral-density (or "moon") filter to dim the dazzling brilliance, and try to see the disk of another planet without a telescope.

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