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Observing with Small Apertures: 130mm and Below

Discussion in 'Telescopes and Mounts' started by Ray of Light, Jul 26, 2016.

Observing with Small Apertures: 130mm and Below

Started by Ray of Light on Jul 26, 2016 at 5:34 AM

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  1. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Yes, that's a poncho - but a cloth one. I don't think that would be terribly effective in the rain, unless one likes wearing a soggy, wet blanket while out in the pouring rain! :D But no accounting for taste, I guess.....

    Looks like you have the same basic weather forecast for the coming week. Here's ours:

    http://forecast.weather.gov/MapClic...3.21206791399965&site=all&smap=1#.VR236ZNZqM8

    But it was 80°F. yesterday. So now we're going to pay for that pleasure. Which will be more rotten because now we're spoiled.

    Ack!

    Dave - getting his big-bag of feathers (Winter-Parka) back onto my coat-rack.....:(
     
  2. Mak the Night

    Mak the Night Well-Known Member

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    Yeah, it seems typical April weather in many ways. It was quite warm here only a few days ago, although it wasn't so warm last night as I waited for the GRS to appear. Had to break out the emergency thermal vests lol.

    jupiter 00 09.jpg
    I had to wait for a lot of cloud to move and it was very damp with a lot of water vapour in the air. So the transparency wasn't brilliant. If I looked directly up at Ursa Major I could distinctly see Alcor though.

    80A 21 11.jpg
    I compared the #80A (30% transmission) with the #21 Orange (46% transmission) and #11 Yellow/Green (78% transmission) using a 6mm Vixen NPL for 150x at an 0.89mm exit pupil. The #11 was particularly good in the northern zones and I thought the image was bright with good contrast. I wasn't so impressed with the #21 though and I thought the image was dark and hard work to define at first. After a while I seemed to be able to discern more and I'll have to experiment more at a later date. I wanted to see if I could get 200x before the clouds rolled in so switched to a TeleVue Barlow/9mm EP combination with the Baader Neodymium filter threaded onto the Barlow.

    9mm Bresser GSO.jpg

    Both the GSO 9mm Plossl and the 9mm Bresser 'Plerfle' focused easily with the helical focuser, which was a relief after the Celestron XL fandango. They both gave bright, sharp images and I couldn't really distinguish between them. The 60° Bresser did exhibit a tiny bit of light scatter but was sharp up to the EOF. So I don't know why Bresser think the 9mm is a bit of a turkey lol. The star was the 8mm TV Plossl of course, giving me 225x. I spent most viewing at 200x as it is about 40x per inch of aperture which is a good general rule of thumb for Jupiter. I called it a night after I'd witnessed the GRS appear. It was so damp my reflex sight dewed over! Plus, I'd forgotten to take my new dew removing hair dryer out with me. Fortunately, it takes some doing to dew a Newtonian. Condensation was running off the OTA as I was packing up. Bloody weather.



    Whatever happened to fishtail parkas anyway? Or for that matter, Mods and Lambrettas?



    Couldn't resist posting Mirror in the Bathroom as it's so good.

    BST 3.2 SLV 6.jpg

    Oh yeah, Pinky & Perky have arrived today along with the Baader filters. The filters look very good. I've experimented with stacking the yellow and green filters and although it seems a little more aggressive than a standard #11 it is a very rich colour. The light blue filter is also very striking. I've compared them with the TS Optics (GSO) filters and the quality of the Baader filters definitely shows.

    fiters1baader.jpg

    I think the Red and Dark blue Baader filters may be too aggressive for reflectors around 5", depending on conditions and target I suppose.

    filters2baader.jpg
     
    Last edited: Apr 18, 2017
  3. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Just wanted to say: I'm enjoying your filter reports. Not many of them about. These should be good for something to do about that old, dusty bunches of coloured-filters many people got ahold of when they first went into this hobby. They seem to have a use afterall!

    I hope our respective weather-patterns improve soon!

    Later folks -

    Dave
     
  4. Mak the Night

    Mak the Night Well-Known Member

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    It's odd that most conversations/threads concerning filters seem to get closed on many forums. I've never understood this. To me, filters are just another tool, which can often be beneficial or not depending on circumstances. Everyone's experiences with anything are subjective, and can often be with astronomy especially. I stopped discussing filters on SGL and won't again, although I will on other forums. In fact, I recently received a review award from one astronomy forum for what I wrote about concerning the Solomark filters. It's a mad world.



    It's sunny a bit here, but there seems to be a lot of light cloud which isn't doing much for the overall transparency.

    jupiter 0000.png

    I'm not totally optimistic for tonight.

    jupiter 0000 2.png

    It will be interesting to test this 4mm AH ortho'.

    4mm AH2.jpg

    Now, if only the April skies let me test this gear ...

    4mm AH 1.jpg

     
  5. Mak the Night

    Mak the Night Well-Known Member

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    Last edited: Apr 21, 2017 at 2:28 PM
  6. Mak the Night

    Mak the Night Well-Known Member

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    jupiterspot.png

    I had a two hour session observing Jupiter up to about fifteen minutes after transit (00:06 BST, 32.6° declination, Virgo). The transparency wasn’t good and it was cool with a lot of water vapour in the air. I couldn’t see Alcor with the naked eye. I had a long session with the 470nm Baader Light Blue filter. Blue light falls between 490 ~ 450 nanometres (the Baader Dark Blue is 435nm).

    baader light blue (1).jpg
    Above: Baader 470nm Light Blue and Baader Neodymium filters.

    The filter seems to me to be a slightly turquoise colour compared to a standard Wratten #80A filter. I find that it is a very pleasant colour to view with. The transmission appears quite high and is probably somewhere between the standard Wratten #80A and #82A filters (30% and 73% respectively). I was quite surprised how much detail the filter allowed me to see in the North Temperate Belt/Zone area.

    baader light blue (2).jpg
    Baader Light Blue filter with TS Optics (GSO) #80A and #82A Wratten filters. The turquoise colour of the Baader 470nm isn't readily apparent in the jpeg above.

    Especially considering the conditions and I was using a 130mm aperture (Newtonian). After a while I increased the magnification from 164x to 200x still using the Baader 470nm filter, effectively changing from an 0.79mm exit pupil to 0.65mm. The Baader filter coped perfectly with this, and the view seemed as good as, if not better, with the increased magnification. I ended the session at 225x with the Baader Neodymium filter as the GRS came into view.

    sombrero.png

    I later searched a bit for M104 which was in the vicinity but I couldn’t find it as the clouds rolled in. All in all, I’m very impressed with the Baader 470nm Light Blue filter for observing Jupiter.
     
    Last edited: Apr 23, 2017 at 9:20 AM
  7. Mak the Night

    Mak the Night Well-Known Member

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    I had a session observing Jupiter for around two hours until transit (00:02 BST). Early on the GRS was visible until about 23:32. At first I used a 164x magnification but soon raised it to 200x. Transparency was relatively poor at first but improved near the end of the session when clouds rolled in effectively ending the session.

    jup mon.jpg

    I stacked the Baader Yellow 495nm Longpass and Green 500nm Bandpass filters to achieve a similar effect to the Wratten #11 Yellow-Green filter. The transmission wasn’t as high as a normal #11 filter I thought, but it gave a very pleasant deep yellow-green colour that seemed to give better contrast than a regular #11. The normally salmon pink GRS was distinctly darker and clearer with the stacked filters and the equatorial zones and bands, particularly the southern temperate zones, were easier to discern detail in.

    Baader yellow green stack.jpg

    I should imagine this combination will be very effective on Saturn. Saturn usually responds well to a #11 Wratten which can emphasise the Cassini Division as well as any surface detail. At the end of the session I switched to 225x (4mm TSO HR shown above) utilising a Baader Neodymium. I then directly compared it with the stacked yellow and green filters using the same eyepiece. Even at an 0.57mm exit pupil with the 4mm TSO the filter displayed just as much detail, if not a tiny bit more, as before. The contrast, by darkening the surrounding background particularly, was superior to just using the Baader Neodymium filter. The nearest thing to the contrast (considering the poor transparency) was when I compared the Baader stack to a TS Optics UCF 1 contrast filter with the same 4mm eyepiece. The UCF 1 gave a more natural view of course.

    TSO UCF (1).jpg
     
  8. Ray of Light

    Ray of Light Well-Known Member

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    Hey guys, been pretty sick. Doing a little better. Be back on soon.
     
  9. Mak the Night

    Mak the Night Well-Known Member

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    Glad you're feeling a bit better Ray. I nearly froze my bollocks off last night viewing Jupiter lol.
    Sombrero.jpg

    I did get to see the Sombrero galaxy though. You'll need 75x ~ 100x to make anything out. You do get a hint of the Sombrero shape with a 130mm aperture, well I did with the Bazooka. You should see more or less the same with your 102mm Meade.



    Weather's turned a bit pants here after going warm earlier for a while. It bloody well hailed today! Chillax and watch this Flo video. Catch you later.

    I don't know what's happened to Dave ... maybe his motherboard has exploded ...
     
  10. Ray of Light

    Ray of Light Well-Known Member

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    Lol! Oh, love Florence. I guess no way I can see the Sombrero with my ST80? I'm probably going to be using that for awhile, once I can breathe again! Good to talk to you again.
     
  11. Ray of Light

    Ray of Light Well-Known Member

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    Great video, thanks Mak!
     
  12. Mak the Night

    Mak the Night Well-Known Member

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    You'll like this!

     
  13. Mak the Night

    Mak the Night Well-Known Member

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    Yeah, I'm glad you're OK Ray, I was starting to get worried. The Sombrero's pretty bright so you should see it with the ST80. I think you need a really large aperture (10 ~ 15") to see the dust lane properly, but you do kind of get the impression of a sombrero hat as you observe it with a smaller aperture. I went up to 100x with the Bazooka but it's good at around 70x. It probably looks pretty good with the ST80. You'll know it when you see it as it is quite bright and definitely not a star.

    sombrero1.jpg

    It makes a sort of triangle with Jupiter and Spica at the moment. Jupiter's difficult to miss so if you can see Jupiter and Spica, M104 is below Jupiter and to the right of Spica as above.

    sombrero2.jpg

    I usually find it with Spica and Porrima (aka Alpha and Gamma Virginis ) making a sort of right angled triangle.

    e73c8857-5496-4b4e-a224-dd714f1eeaef.jpg

    Apparently, it looks like this with a 16" aperture. It wasn't quite this good for me lol.

    http://www.pbase.com/mike73/image/155538415
     
    Last edited: Apr 26, 2017 at 9:45 AM

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