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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. Mak the Night

    Mak the Night Well-Known Member

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    That #21 Hoya sounds good. I have no idea where Orion source their filters from nowadays. I'm fairly sure Synta source their kit filters from Barsta.

    The GSO Wratten #21 Orange only has a transmission rate of 46% and can be difficult when the transparency isn't so good. I guess it might be OK on Mars with a reflector of around 150mm.

    I don't know the transmission rate of the Baader 570nm Longpass, they usually exaggerate everything in their own blurbs lol. It must be pretty high though as I could definitely see starkly contrasted surface detail in dodgy transparency.

    I had another session last night but it was over in about 20 mins. It had been a clear sky all day ... until about 20:00. Bloody typical.

    I'd give the orange filter a go on Mars Dave, if you get the chance. I was rather surprised with it. Red filters are supposedly good as well. Might be pushing it on a 150mm f/6 Newtonian though.
     
  2. Mak the Night

    Mak the Night Well-Known Member

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    mars friday.png

    I got a third fairly decent observation of Mars on Friday, between around 19:45 ~ 21:15 BST. The seeing was a relatively good A~II although the transparency could have been better. The phase, the southern polar cap, and the dark area around Terra Sirenum were all pretty easy to make out. I didn’t think the darker surface features were as clear as earlier in the week. This was probably a transparency issue. I also got a chance to compare my 4mm TS Optics (Barsta) Planetary HR with the 4mm Astro Hutech orthoscopic.

    IMG_20180929_113233.jpg

    The 58° Barsta was certainly more comfortable to stare through for over an hour lol. To be honest, I couldn’t tell any real difference between these two eyepieces.

    IMG_20180929_113414.jpg

    The sharpness, colour, definition and overall contrast seemed the same to me. From an ergonomic perspective the Planetary HR won overall for sheer comfort value. I think when you are relaxed and as stress free as possible more detail can be perceived in a prolonged observing session.

    IMG_20180929_114252.jpg

    I also got to test some more Baader filters:

    Baader Orange Longpass 570nm
    Baader Red Longpass 610nm
    Baader Green 500nm Bandpass
    Baader Single Polariser

    The orange filter really did contrast dark surface features well, probably better than any other filter, including the TeleVue Bandmate. It’s now possibly my favourite Mars filter lol. Furthermore, it actually seemed to sharpen the southern polar cap outline, making it very distinct and easy to discern. The red filter was very similar to the orange but darkened the image somewhat. I expected this with an f/6, 150mm Newtonian though. The polariser was interesting; in the dark I mistook it for the green filter. I wondered why the colour seemed so natural with it! The green filter was also quite interesting, it reminded me a bit of the #11 yellow-green. Apparently yellow and green filters are useful for revealing low altitude orographic clouds. I thought I could see a small, bright, white albedo feature in the north west of the planet with the green filter.

    mars albedo.png

    I don’t know whether these were clouds or some other feature. It wasn’t as easy to see with the red and orange filters. I ended the session using the Baader Contrast Booster stacked with the single polariser.

    Images from Cartes du Ciel & Virtual Planet Atlas
     
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  3. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Very nice spread, Mak! Me like! The contrast of size between the 4mm Orthoscopice and the 4mm TS Optics Planetary is amazing. You really think the Barsta Planetary and the Orthoscopic are equal in what they'll reveal and general comfort? I'd like to hear more on this issue - if you get a chance.

    And I always enjoy viewing good "Filter-Porn," as I'm sure you know....:eek: :D...
     
  4. Mak the Night

    Mak the Night Well-Known Member

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    Thanks Dave, I knew you'd like the filter pr0n lol. I was most impressed with the Baader Orange Longpass 570nm filter on Mars, especially as I had a decent amount of time to evaluate it.

    It's like I told Ray years ago (Ray wore glasses), the Barsta 58° seem as good as Japanese orthoscopics to look through. I think the Barsta EP's are only 5 element anyway, so fairly simple with good light transmission. For planetary viewing (or DSO) I think they are at least as good as an orthoscopic. They seem to give identical contrast to an ortho' to my eyes. They can have a tendency for a tiny bit of false colour on a bright Moon with my f/6 Newtonian, which the orthoscopics don't seem to suffer from. But that has to be weighed against the extra comfort factor of the Barsta EP's. Squinting through a tiny orthoscopic for 90 mins can be a bit of an ordeal lol. It was a luxury to use the 4mm Barsta on Mars and have a twist-movable eyeguard! Let alone a large eye lens and a whole 58° FOV.
     
    Last edited: Sep 30, 2018
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  5. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Those Barsta Planetary EP's are the same as my Astromania's and other brand-names, as we've deduced before. As I said then, I have the 6mm and the 9mm - and wish I could justify buying more! But I cannot. But I'd gladly get something like the Barsta rather than squashing my eyeball up against the 4mm Orthoscopic! :p It looks like something a teenage sex-maniac would drill in the wall from his dorm-room into the Women's Changing-Room. :eek: :D

    A Wratten #21 Orange-Filter is an excellent colour-filter for use on Mars. And very commonly recommended for just that. If anyone out there reading this when Mars is due for good showing in your part of the sky, check your inventory of goodies and be sure you have one and it's in good condition! If you need one - I suggest you look at the GSO #21 Orange-Filter. And the price is most agreeable to most everyone's budget! You don't need to spend a fortune to get well outfitted in terms of filters.
     
  6. Mak the Night

    Mak the Night Well-Known Member

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    I dunno Dave, Christmas is around the corner, treat yourself to another Barsta 58° EP. I don't know why I didn't think of orange filters for Mars before. They're good for twilight lunar viewing as well.
     
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  7. Dave In Vermont

    Dave In Vermont Well-Known Member

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    My #21 is another Hoya from Japan from around 2001-ish. Still in 'A-1' condition. I've been checking out my collection of color planetary-filters every-time one gets brought to my attention as of late - after I ran into those streaky & spotted Pro-Optics popped-out at me - both replaced now with the GSO's. In fact, Agena just published my review of the GSO #23A. They just published my review of the #8 Lt. Yellow GSO a few days back. I'd think they'd be tired of me by now! :D

    Thank's for your further review of the Barsta Planetary vs. Orthoscopic's. You should consider writing a full-on article of your experiences with these. I'm certain it would be of great use to many of us 'tube-jockeys' who find the old Orthoscopics' impossible to deal with in the shorter F.L.s' like 4mm or 6mm. And the prices on the Barsta's is quite agreeable too.

    Win ~ Win! Thanks' again!
     
  8. Mak the Night

    Mak the Night Well-Known Member

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    I might do a write up later on, after more evaluation.

    focus.jpg

    I'm also pretty sure the insides/lens groups are exactly the same as the 'Sky-Watcher' UWA series. These are Barsta too. The view is the same, although I don't think they are flocked as well internally.
     
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  9. Dave In Vermont

    Dave In Vermont Well-Known Member

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    I well remember back in 1970 - 1973 when my parents allowed me to get a 3" F'15 Edscorp' Refractor (with a Carton Optical Achromat - same as Unitron & many others), I trapped them into putting up the $$$ for a few eyepieces. There was no TeleVue® or SkyWatcher, no nothing resembling most EP's of today. Top-end were a few Orthoscopics - little things - same as today. Most of us starting out had Ramsden EP's. Huygenian was what you got with a scope. Top-end 'come-with' EP's were Ramsden's.

    It was an exciting day when my "rents'' gave me the money to go 13 miles into Boston and buy a Kellner 9mm. And this to a dusty, old place called Boston Optical. From the dusty, old owner of the shop - I took delivery. It had been on 'special order' for a week or two. I wished to get an Orthoscopic or 3. THAT was laughed at by my parents. Those cost about $35.00 apiece!

    Then home I crawled - through the MBTA (the Metropolitan Boston Transit Authority). And began waiting for - what else? - a clear night. Wearing my sickle & hammer jacket.....


    Raul
     
  10. Mak the Night

    Mak the Night Well-Known Member

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    sunday000300a.png

    It was a tad frosty but clear this morning between 00:00 & 03:00 BST. So I took the ED72 out. I started off with a low Summer Triangle. Mostly I just swept the Milky Way, open clusters, and other areas of interest with the 2" Baader 36mm Aspheric (11.6x). Cassiopeia is virtually near the zenith. Weirdly I kept 'bumping' into a very high Andromeda Galaxy lol. M42 was good at 11.6x, 22x and 60x though. It wasn't until around 02:00 that I needed the dew heaters. I used the 2" Baader UHC-S on M42. It isn't quite as 'green' as the Orion SkyGlow. Transparency wasn't as good as I'd liked. I even had M42 to 105x but the hazy transparency was really beginning to show. I had a short fling sweeping with the 19mm Panoptic at about 22x. I ended the session sweeping around Cassiopeia and Perseus and finally the Double Cluster with a 28mm LET for 15x. By this time one of my handwarmers needed recharging.
     
    Last edited: Oct 7, 2018
  11. Mak the Night

    Mak the Night Well-Known Member

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    444309a1-ce7a-4dfe-9387-f021c310355e.png

    It may just be that I will be the proud owner of a 32mm GSO 'RK' (Reversed Kellner?) eyepiece soon.

    32kellner bollocks.png

    These things are really unfashionable, so no one stocks them anymore apparently.
     
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  12. Dave In Vermont

    Dave In Vermont Well-Known Member

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    "Unfashionable?" Looks good to me! :p

    I want one too!
     
  13. Mak the Night

    Mak the Night Well-Known Member

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    It arrived today. The first thing I did was swap its undercut drawtube with the smooth one from the GSO Barlow.

    pair.jpg

    The drawtubes are identical except for the undercut. I believe Agena sell these:

    7a80b250-51ee-4f9c-a7db-2b56145b60a9.png

    https://agenaastro.com/gso-chrome-barrel.html

    I'm pretty sure they're aluminium rather than chrome.

    k1.jpg

    It's fairly light in weight and in daylight tests gives a sharp, bright view in the 72ED. The eyeguard is very soft plastic and crumples nicely as you place your eye on it. It will fold down if you persevere with it but I quite liked it in its 'up' position. I make the field stop 40mm, which is 8mm more than the 31mm Baader Hyperion Aspheric. I'm not sure of the FOV but I'm guessing 58° as that seems to be standard for most reversed Kellners.

    barlow.jpg

    This is probably how I'll use it the most. Adding the 2" GSO Barlow element does add to the overall weight, but it is still lighter than the 19mm Celestron Luminos.

    weight.jpg

    Indoor weight/balance trials seem fine and I have no trouble manipulating the ED72 on the AZ5 with the Kellner/Barlow combination in the diagonal. Visual daylight trials with the combination seem good with no visible vignetting. The combination gives 19.6x on the 72ED. Whether there will be noticeable off axis astigmatism in an f/5.8 refractor is difficult to say without actually using it in on star fields. The Barlow may help alleviate any seagulls though lol.
     
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  14. Mak the Night

    Mak the Night Well-Known Member

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    Revision: I believe it has a 55° ~ 56° FOV.
     
    Last edited: Oct 18, 2018
  15. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Now that's what I call a good looking telescope! And functional scope-porn at that. What's not to love? :p
     
  16. Mak the Night

    Mak the Night Well-Known Member

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  17. Dave In Vermont

    Dave In Vermont Well-Known Member

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    Beginners are in the enviable position these days. So many nice astro-goods are available these days - before the name and greenletters of 'TeleVue® intrudes upon their utopian bliss. Alas! :p

    Those Meade eyepiece & filter sets make a very good example.

    Eye's to the Skies!

    D.
     
  18. Mak the Night

    Mak the Night Well-Known Member

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    And most of it comes from here:

    Screenshot 2018-10-18 at 22.15.24.png
     
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  19. kevan hubbard

    kevan hubbard Well-Known Member

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    I don't know about Busta gonad but I once saw Busta blood vessel.
     
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  20. Mak the Night

    Mak the Night Well-Known Member

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