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#1 McDoggin

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Posted 17 October 2013 - 06:58 PM

The following is from Matroskin:

"Hurray! This night was clean and I worked with the telescope on my balcony testing UHC filter. You know, I like the effect. The light pollution level here is rather high (city's size is near a million citizens). Usually in my LT 8 SC, when I watch from the balcony, M42 (Great Orion Nebula) looks like triangle with a dark hollow on one side. But with the UHC filter I instantly saw "wings" (or as somebody calls this detail "a moustache") spreading from the center triangle. Sure the image was not as astonishing as in the real dark place far from the light pollution, but it was a good compromise in my opinion. PS Alignment procedure - 1-star (Betelgeuse), quick and precise. Watched М35, М67, М44, NGC2169, Juppiter, Mars. Tried to find the comet (ISON C/2012) but failed. I suppose it's still too faint for viewing from the city.

P.S. http://astrodummies....3/2013-10-15-31"


What is the brand of the UHC filter that you bought? and why did you choose that one? Also the picture of Jupiter is good! Did you use a DSLR with an adapter or some other type of imager? I would like to be able to take similar photos. By the way I too could not find ISON a few days ago... It was pretty dark in my location but still no luck. Also I had a similar experience with Mars, I think for me it was too close to the horizon so there was a lot of atmosphere to look through and I could not get a good focus. At higher magnifications I have a big issue with jitter when I adjust the focus. The focus knob is very sensitive and when touched perturbes the image. This happens so much so that it is often very difficult to get a good focus. Typically this happens when I try to use eyepieces that have a focal length of 8mm or less. I have been thinking about an electric focuser : http://www.jmitelesc...ages/mf_lx2.jpg

I have been using "StarGPS" and it works great. If anyone has questions about it I will do my best to answer...

#2 Matroskin

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Posted 17 October 2013 - 07:29 PM

I have a "Levenhuk Ra" 1.25" UHC filter and this is my first UHC so for me it is hard to compare. I observed deepsky objects with UHC via my friends telescopes (200 and 250 mm Newtonians), but they use 2" filters and they are f/5, so it is hard to say if this Levenhuk 1.25" UHC is better or not. I have already tested it on M42 and plan to test it on M33 (due to it's low contrast) and some small objects like Blue Snowball (NGC7662) or Clown Face (NGC2392). As I mentioned eralier, on M42 results are rather impressive.

http://www.levenhuk....uk-ra-uhc-1-25/

About Jupiter - I used my Canon 600D DSLR on T-adaptor. It was 1-minute long video (ISO 200, exposition 1/80) later been stacked and processed in Registax 6 software (10% best frames). About Mars - I think it is too small now, will wait for opposition (April 2014) and then I hope I will make some more serious pictures.

An electric focuser - a brilliant idea! I wonder if there are ones for LT series - in the Internet I saw Meade motorized focusers for LS and LX, but not for LTs... For the precise focusing I use Bahtinov's mask with a small magnetic ring - it is very easy to put the mask in front of the corrector lens and accurately put it off after a focusing process is finished. Here's my accessoires set - eyepieces (Meade 4000 series 40, 30, 26, 15, 12, 9 and 6 mm plus Ortoscopic 7 mm), 2x Barlow lens, T-adaptor, filters (neutral, blue, green, red, yellow, UHC) and Bahtinov's mask. http://astrodummies....om/2013-07-31-9

#3 McDoggin

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Posted 22 October 2013 - 04:55 AM

After doing some research I think the filter that you bought has an optimal pass band for viewing nebulae and the price is good toofile:///C:/Users/macleanw/AppData/Local/Temp/msohtmlclip1/01/clip_image001.png. From what I understand many nebula have emission lines at 486.1nm, 496.9nm and 500.7nm so that's right where you want to have the pass band of the filter. I was also looking at the Orion UltraBlock but it is $10 more and has the same pass band. There are other filters that have an additional pass band around 650nm but from what I understand it is better to have one narrow pass band rather than a more general purpose filter with wider or multiple bands. I might consider also getting a specific "OIII" filter with an even narrower pass band. I was also looking at a filter selector: http://www.adorama.c...CFVRnOgodJU0A9g so that I could rapidly switch between filters to achieve the optimal effect. I have a set of color filters that are useful for planetary and lunar viewing but I have not tried them on M42 yet since it tends to be faint to begin with.
As far as the electric focuser goes I think the Meade version for the LS requires the camera and uses it to automatically focus. The link above from JMI is the only electric focuser made for the LT that I know of. There are also some replacement manual focusers that I was looking at that reviewers claim reduce jitter : http://starlightinst...&product_id=120. The only problem I see here is that it requires disassembly of the existing focus knob and that looks a little too scary for me. Then there is also the added fine Crayford focuser which would slip onto the rear cell of the OTA: http://www.telescope...fordfocuser.cfm. I think this would be more manageable and probably allow fine focusing without massive jitter.
Bahtinov's mask is a great idea and I had never heard of it before; I will definitely pick one up.
My accessory set: 2x Barlow, Baader planetarium hyperion zoom eyepiece 8-24mm, YRGB color filters, 5mm Orion Stratus wide field eyepiece, and the Meade 4000 26mm eyepiece. After writing this I realize how covetous I have become for astronomical gear! Additionally I am thinking about changing over to 2" eyepieces + diagonal before I invest much more in the 1.25" gear I have.

#4 Matroskin

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Posted 22 October 2013 - 08:44 AM

Yes, 2" accessoires they are very attractive. And maybe my next upgrade will be a 2" adaptor with a dielectric diagonal mirror - for I could,.for example, try to exchange eyepieces from my friends having Newtonians. But not now. The sky is the number one - and again heavy clouds without a chance to see any single star. 2", 1.25"... even 0.2" or the binoculars - no difference. PS Bahtinov's mask - this simple device I recommend to have. Very precise and inexpesive (and quick) manual focusing, especially for taking pictures. PPS My friends have Newtonian f/5 8" equatorial Newtonian setups with motorized focusing, computerized slewing and so on - but it means a heavy bunch of cables and so on... over than 250 pounds weight. I do not want this.





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