Jump to content

Stargazers Lounge Uses Cookies

Like most websites, SGL uses cookies in order to deliver a secure, personalised service, to provide social media functions and to analyse our traffic. Continued use of SGL indicates your acceptance of our cookie policy.

sgl_imaging_challenge_banner_beauty_night_skies.thumb.jpg.2711ade15e31d01524e7dc52d15c4217.jpg

Alan64

Members
  • Content Count

    1,246
  • Joined

  • Last visited

Posts posted by Alan64


  1. Oh, the motor-drive; my bad.  I have this Celestron motor-drive kit...

    7a.jpg.544392db9aa4176915fbf084fcc19630.jpg

    I haven't used it yet.  It comes with two mounting-brackets, one for an EQ-1, and the other for an EQ-2.  I have both types of mounts, therefore I'm set.  That's one of the the most economical drives for an EQ-2...

    https://www.astroshop.eu/drive-motors/celestron-motor-drive-for-eq-astromaster-and-powerseeker-mounts/p,15464

    It will work with any brand of EQ-2.  The Sky-Watcher kit costs a good bit less, and would also work with any brand of EQ-2...

    https://www.astroshop.eu/drive-motors/skywatcher-eq-2-ra-motor-drive/p,1532

    This is a more deluxe kit for an EQ-2... https://www.teleskop-express.de/shop/product_info.php/info/p2934_Skywatcher-Quartz-controlled-RA-axis-tracking-motor-for-EQ-2-Mount.html

    But with the other two less-costly kits, the tracking speed can be adjusted, fine-tuned.  The deluxe kit reportedly does not need adjusting.  Still, I'd rather have the ability to adjust.


  2. I have a Meade "Polaris" 90/900 OTA, as a liquidated second from a vendor affiliated with Meade...

    kit2.jpg.bf37e2925a5ed29adc47874b9a005aae.jpg

    ...and for €58.  After I had renovated it, to improve the contrast and collimation, the optical quality, of the doublet-lens, has blown me away.  Quite a surprise that one, given its humble origins.  That's the mount that comes with it, an EQ-2, and just like that of the Sky-Watcher, and the Celestron even, but that particular mount originally came with my Meade 114mm f/8 "Polaris" kit, a Newtonian...

    kit4.jpg.0325a2bb0ec63e08402a4733d92c96d8.jpg

    That kit usually costs less than the Meade 90/900 kit, and is a fine telescope in its own right; a little brighter than a 90/900 refractor it is.

    The Meade 90/900 refractor comes with an all-metal focusser; a plus.  The Sky-Watcher may as well, but the Celestron does not; it's of plastic.  I, too, would avoid the Celestron kit.

    That EQ-2 of mine arrived with its axes bound up, tight; also with a wonky DEC shaft, the threaded base for it actually.  The EQ-2 that comes with the Sky-Watcher may arrive a bit off-kilter as well.  All three EQ-2s may very well need to be adjusted, loosened or tightened, depending, upon arrival.  The mounts are quite mechanical, like a clock, therefore a lot can go wrong, but they can be renovated; a bit of DIY work.

    In general, a 90/900 refractor is a fine choice for those first starting out.


  3. I have an EQ-3, a Celestron CG-4...

    mount-head.jpg.746b4ba80f210bf5f6186465ae6a7cc7.jpg

    Don't be worried about the difference between an EQ-3 and an EQ3-2, as there really isn't a difference, at least where a motor-drive is concerned.  For visual-use, and perhaps even for imaging if inclined, I would motorise only the RA-axis...

    https://www.firstlightoptics.com/all-mounts-motors/single-axis-dc-motor-drive-for-eq3-2.html

    I have read where someone used one of these drives for an EQ-3, and successfully...

    https://www.firstlightoptics.com/celestron-astromaster-series/motor-drive-celestron-astromaster-geq-93514.html

    However, the mounting-brackets that come with it, one for an EQ-1, and the other for an EQ-2, will need to modified, if not a new bracket fashioned outright.

    That drive has a speed-control, and for fine-tuning the rate at which an object is tracked; other drives do not.  But there is just one thing: the worm-shaft, where you would attach a slow-motion control, and the RA-gear, must rotate and turn easily, freely and smoothly, with no slop or binding.  With the mount unloaded, with no counterweight attached, you should be able to twist the worm-shaft with your fingers...

     1171282336_twisthere.jpg.6e0a6543d1fe61b8e7fe3e82715da932.jpg

    If you cannot, you will need to make adjustments until you are able, else damage can result to the motor's gears and the motor itself.  I took my EQ-3 apart a while back, and removed the factory grease and replaced it with a quality grease, such as Super Lube.  That's what I use for all of my mounts, and it works a charm.  These equatorial mounts are quite mechanical, like a clock, and all that that entails.

    • Like 1
    • Thanks 1

  4. I have an Orion 150mm f/5 Newtonian, and here upon an alt-azimuth that's quite comparable to your own...

    221979423_6f5qa.jpg.14686e677efc83db6790ffeffbbded59.jpg

    Both of our telescopes are produced by Synta, as are those branded "Sky-Watcher".  This is the collimation scene of my own upon its arrival in 2012, and well-collimated at that; almost perfect, but I can't take the credit...

    collimation1a.jpg.96234038dfa84a14d293c6098401b8f2.jpg

    Note the lighter circle with the "bull's eye".  That's the reflective underside of the collimation-cap, and that came with the telescope.  Outside of that, the black circle which is the shadow of the secondary-mirror.  You see it as a shadow because it is hosting the scene.  The much larger white area beyond that is the main, primary mirror, and with its rubber retaining-clips.  Then, note how the lighter circle there in the center, with the "bull's eye", is not quite centered within the secondary-mirror's shadow.  That is known as the "secondary off-setting".  It is necessary for shorter, faster Newtonians.  Fortunately, the off-setting occurs automatically when collimating...

    https://www.skyandtelescope.com/astronomy-equipment/offsetting-your-secondary-mirror/

    The purpose of the off-setting is quite simple, and to ensure that all of the light gathered by the primary-mirror reaches the eye.  Again, the off-setting occurs automatically, although there are advanced users who like to tweak it further.  

    If the telescope is collimated to near perfection, you can conceivably realise up to at least 50x per inch, which translates to a power of 300x, particularly whilst observing the Moon, as the body is quite close to Earth...

    750mm ÷ 300x =  a 2.5mm eyepiece

    Such dedicated eyepieces do exist, although, granted, even though the opportunity to employ such a high power is rare, it may occur nonetheless, and then to see with your own eyes what very few people have seen before.

    I use a 12mm wide-angle eyepiece combined with a 3x barlow, and for a simulated 4mm.  For a simulated 3mm, a 9mm combined with a 3x barlow; an 8mm, then a 2.6mm is realised.

    Generally all of the wide-angle, short focal-length eyepieces that are vended online have barlowing lens-elements integrated, therefore no need for a barlow; for example...

    https://www.firstlightoptics.com/bst-starguider-eyepieces/bst-starguider-60-32mm-ed-eyepiece.html (234x)

    Would a mere 234x seem insurmountable?  Not too long ago, and after I had collimated it, I took this afocal shot of the Moon, through the bundled 4mm Ramsden(?) eyepiece with a small point-and-shoot camera, at 250x, and with a Celestron 5" reflector...

    1447475264_071119-bundled4mm.jpg.e1d7b712631cf94e0cdc5ffbfab5e3bf.jpg

    The live view was tack-sharp.  I had to deal with a shaky mount whilst taking that shot with the camera.

    The ultimate goal in collimating a Newtonian, and as spot-on as possible, is to make practical use of a great capability hidden within.  It's there, waiting. 


  5. On 09/08/2019 at 08:41, ju1234 said:
    Hello, I just received new Powerseeker 127EQ. The tube rings that it came with have perhaps 1/8" screws at the bottom which is supposed to go into the hole in the top of EQ mount (mine is perhaps EQ type 2). The flat portion of the ring sits on top of the mount and not inside the recessed area. That leaves the tube to be moving easily. Is this normal? The instruction manual says "mounting bracket with tube rings", however I do not see any thing in the package that can be considered "mounting bracket".

    Also the hole is not tight around the screw, there is some play. It is just a butterfly/thumb nut on the bottom that holds this. Which means the tube will be able to move in long axis as well as side axis. Even slight movement can throw the target completely off the field of view. Any suggestions.

    Thank you.
     

    Hello,

    I got the same kit last February.  The video above should help you with your immediate issue.  This is the mounting-saddle in question...

    536518565_mountingsaddle.jpg.163db7b5bd6f2b7eca508faac4a06627.jpg

    Have you observed with the telescope yet?  If so, how are the views?


  6. For your lowest power, for the hunt, get a 32mm Plossl.  It will give you a power of 20x, binocular-like, and to find your way around the sky...

    Focal-length of telescope: 650mm ÷ 32mm = 20x...

    https://www.365astronomy.com/32mm-GSO-Plossl-Eyepiece.html

    The 20mm that came with your kit is an erect-image eyepiece, for daytime/terrestrial use; birds in trees, ships at sea, that sort of thing.  I have the same one, and that came with my Celestron 127mm f/8 "Bird Jones".  It has a rather narrow field-of-view.  You can replace it with a wide-angle 20mm if you'd like, and for the sky at night.

    What type of 4mm eyepiece do you have?  I usually 3x-barlow a wide-angle 12mm for a simulated 4mm, which is much more comfortable to use.  In any event, you can make good use of 2x and 3x barlows, for the Moon, the planets, and the double-stars, and per the telescope's rather short, 650mm focal-length.

     


  7. On 05/08/2019 at 16:10, DarkNorth said:

    1 Question, is the scope easily able to be moved to an alternative mount? I mean by default it just rests on its current mount, I've seen simialr scopes with different stands - almost like a different stand was bought for it.

    My apologies, as I didn't see that question initially.  Ordinarily no, as it would require something of a Herculean feat to accomplish.  I assume you mean mounting the OTA onto a tripod-type mount.  If so, you'd have to remove the trunnions from the OTA, get tube-rings and a dovetail-bar, and mount it onto an EQ-6.  This is an EQ-6...

    https://www.firstlightoptics.com/skywatcher-mounts/skywatcher-eq6-r-pro-synscan-go-to-equatorial-mount.html

    Otherwise, it is destined to remain as is.  Now, a 200mm f/5 is a different story.  The tube is 200mm shorter, and is actually sold together with a smaller EQ-5 in kit-form...

    https://www.firstlightoptics.com/reflectors/skywatcher-explorer-200p-eq5.html


  8. 11 minutes ago, DarkNorth said:

    I have skymap on my phone which is fairly accurate. certyainly to the right area of sky. accuracy depends on the phones internal gyro's.

    I have a trolley just like that I use for my computer - if thats all others use, I guess I just need to get it out of the loft.

    Thankyou for the app link - no I'd not seen that one. Though I found something I found interestinmg earlier. I was looking for a 'real loo' of the solar system with real orbits as I didn't believe every planetary body was on the same orbit - it came close to what I wanted showing bodies that go above and below what might be deeemed the earth orbit horizon.

    https://www.solarsystemscope.com/

    I thought there was some planets not quite on perfect orbits- I know Pluto comes inside of Neptune at some points but I can't find a good 'true' solar system atm.

    Stellarium is a very popular program.  Just ask round.  Check it out; you've nothing to lose.  I found M13 with it, and was observing the object within 30 minutes or less as a result.  Stellarium is also available as an app for a phone.

    It takes a 16"/400mm "Dobsonian" to see Pluto, however, but still as a tiny dot.  Uranus is easy enough, but Neptune a bit more difficult, but doable I think with a 200mm aperture.


  9. Of the three designs commonly encountered, telescopes in general come in all shapes and sizes.  I have this short, fast 6" f/5 Newtonian, and on a tripod-type alt-azimuth...

    1252361524_6f5ra.jpg.890d8c72ecf930cbfd7530ba8e46991c.jpg

    Alt-azimuth mounts are simple to use, and in directing the telescope up and down and left to right.  When tracking, I refer to its motions as the "staircase" method.

    This is an example of a longer, slower Newtonian, and on an equatorial mount...

    1753122472_6f10b.jpg.248d4a862f9ccbecfba995faa983e760.jpg

    Equatorial mounts are not as simple to use, but they do allow one to track objects automatically with a motor-drive attached, keeping an object centered in the eyepiece for as long as they like.  The motions are also much smoother...

    44215629_mountmotions2.jpg.998d28ddc194029e6edd21db7e8bf51b.jpg

    ...and as the telescope tracks across the sky.  Both types of mounts come in manual mode, where you use your hands to direct the telescope, and in a motor-driven mode, often with a computer integrated, or just a simple motor-drive.

    The mount of a "Dobsonian" is a Dobson-type alt-azimuth, hence the telescope's moniker, and is usually constructed with rather heavy, plastic-covered particle-board, like that found in put-together furniture kits...

    457205020_6f5w2a.jpg.9f5e631b1b5a23f53191fbbaee2eded4.jpg

    Dobson alt-azimuth mounts are ground-based, without a tripod.  Whilst heavy, they are also quite sturdy and supportive of the telescope, and dead-simple to operate. 

    This is a rather nifty kit.  6" of aperture puts on quite a show under darker skies, as I have experienced...

    https://www.amazon.com/Celestron-Omni-XLT-150-Telescope/dp/B000NMOIP8/ref=asc_df_B000NMOIP8/?tag=hyprod-20&linkCode=df0&hvadid=312066954908&hvpos=1o3&hvnetw=g&hvrand=2157160566106243571&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9013737&hvtargid=pla-568711483159&psc=1

    With the equatorial, you can attach a motor-drive, and keep the objects centered there in the eyepiece, motionless.  That way, when you want to show something to your family and friends, they wouldn't have to bump and nudge the telescope to find it again.  In my view, manual mounts are a one-person affair.

    With refractors and Newtonians, what you see is what you get.  With a short telescope, the lower powers are favoured.  With a long telescope, the higher powers predominate.  With that 6" f/5 Newtonian, you can have both, from a low power of 19x(binocular-like), up to 200x and beyond with the aid of 2x and 3x barlows(microscope-like); and for observing the gamut, practically every object in the sky, satisfactorily. 


  10. 5 minutes ago, DarkNorth said:

    Thats likely to be my next step, at present I have help - as I'm at home with my parents atm my Dad has done the carrying (yes went ahead of this scope) it's not heavy - more awkward than anything. My issue isn't the weight - My issue is more I am a TPN Patient, namely I am attached to night feeds for nutrition. So I'm attached to a bag of fluid - ok I could put it on my back anmd that would make things easier - I usually weheel it around like  a suitcase but its pretty difficult to move both my feed and telescope - so transport is my next problem to sort. I can make things a little easier for myself atm putting my feed on my back though.

    I have quite successful;ly viewed Jupiter and Saturn of which I am quite chiffed as a beginner to see - I always knew they were planets so found it easy to pick them out. It's just the fun of moving with the earth rotation,. Unfortunately my back garden really only has a good view in the southern sky, the north I don't get much at horizon level - Probably can't see much below 45degrees or more. So anything low on the horizon like Venus/Mercury even at Sunset can't be done. Mars isn't the best time. I think I had Pluto on the scope too - but its so small it's hard to know if it was the planet or a distant star. Uranus/Neptune  (I think Neptune was in the north sky) when I finally was able to view on a clear day was no longer in my field of vision.
    As is Mars but I gather 2020 is a better time to see Mars anyway - I've seen it with the naked eye numerous times. Venus It would be nice to see phases where possible if it comes into my vision. In the short term its just back yard scoping. Longer term I'll try to go to other places. I am in an urban area but its not massively bright but I still don't feel I can see the milkway where I am. (The North West of Hartlepool).

    If theres suggestions for transport - I''ll take a look I have a trailer I used for computer transport. It probably would do the job but I can't say for sure whether its suitable until I  have an idea what other options there maybe.

    Incidentally is there recommendations for particular things to look for in the sky? West and East I'm surrounded by walls at home so it's mostly South and high angle to the North - I could see more of the North and East if I went to the front of the house though - possibly.



     

    I, too, have a washed-out sky to the north...

    north3.jpg.14a6bfcc061a8d98522f33138422f296.jpg

    ...and "courtesy" of a major crime-ridden city, but I am able to see Polaris, the North Star, and there above and askew of that distant back-lit tree at center.  Though land-locked as I am, aside from the major river snaking through nearby, I nonetheless feel like a sailor, a celestial stowaway, and upon the high seas approaching Shangri-La.  I have walls surrounding my digs, and in the form of trees planted in the mid-1990s.  But I am able to peek through them to the east and south, for this sprite and that.  The west is blocked by the house, and more trees, but that's where everything in the sky sets, including the Sun, and therefore of no real consequence.

    I don't think any of the planets transit in the northern part of the sky.  I always see them in the south, transiting from east to west.  The planets are also quite low in the sky at this time, and for the next few years I've read.  Here, they're not quite as low as they are further northward, but the lowering has been noticeable.    

    This is one method of hauling a kit round the lay...

    post-245546-0-20923700-1535864570.jpg

    If you haven't already, you may wish to download this program...

    https://stellarium.org/

    Once gotten the hang of, the program will show you when and where all the objects are in the sky, and it's free.  Simply choose your PC operating-system there at the top right of the page.

    One object to shoot for is M13, the great globular-cluster in the constellation of Hercules.  It appears a bit high towards the west in the early evening.  Here, it is shown as it appears in your location at about midnight...

    https://i.imgur.com/5Z5OPSj.png


  11. A list of astronomy clubs in your area...

    https://www.go-astronomy.com/astro-clubs-state.php?State=IL

    That is, if you have a mind to and the time to engage in such.

    Otherwise, there are only three designs of telescopes in the marketplace from which to choose, examples of which that have already been presented.  Telescopes are not like everyday items that are mass-produced.  Take breakfast cereals for instance.  There are more types of those on store shelves than you can shake a stick at; types of snack foods, too.  Whilst there are many telescopes for sale online, or within a brick-and-mortar shop locally, all of them fall under those few, three designs.  I started with a refractor, an achromat, and at the innocent, tender age of 9...

    kit.jpg.53c9d5cfc7468fb4f58311b9f6678885.jpg

    As you can see, it's been through the wringer.  I saw Saturn for the first time with that one, the very first object I ever saw, and with my late father.

    Any questions?  We're here to help.  We love to help those first starting out.


  12. 8 hours ago, Istand4Flag said:

    But also would like something family and friends can look through when they come to visit.

    I wanted to address that aspect separately.  Yes, share your experience with others.  There are many folks who conduct outreach with their telescopes, in encouraging others to look skyward.  The goal is to share their own experience and excitement, and to encourage others to consider having their own telescope for use at their homes, or to travel with even.  Here's another 8" "Dobsonian" that might interest you...

    https://telescopes.net/store/explore-scientific-firstlight-8-dobsonian.html

    That one has a rather innovative, and unique way of mounting the telescope, with tube-rings and rocker-trunnions, which would enable you to rotate the focusser, into most any position, and for more comfortable viewing for you and your family and friends.

    There are also 10" "Dobsonians" available, and that would also knock your socks off under a dark sky.

     

    • Like 1
    • Thanks 1

  13. There are three types of telescopes to consider at the stated budget: refractors, Newtonians/"Dobsonians", and Maksutov-Cassegrains.  The first two designs have been around since 1608 and 1668, respectively; the last, a Maksutov, was first developed in 1941.  I have examples of all three.  

    Refractors use lenses to form an image.  Newtonians use mirrors.  Maksutovs use both.  For the outlay, a refractor would have the smallest aperture, whilst a Newtonian would offer the largest.  A 4" achromatic-refractor and mount would cost the same as a 8" Newtonian on a Dobson mount, aka a "Dobsonian".

    The refractor... https://www.amazon.com/Celestron-21088-Omni-XLT/dp/B000NMOIOE/ref=sr_1_fkmr0_2?keywords=celestron+omni+xlt+102+eq&qid=1564941319&s=electronics&sr=1-2-fkmr0

    Refractors are generally what folks think of when they hear the word "telescope".  They require virtually no maintenance, they offer the sharpest and most contrasty images over all other designs, and are ready to observe with in about 15 minutes, if not immediately, and after taking it outdoors.

    The Newtonian/"Dobsonian"... https://www.amazon.com/Zhumell-Deluxe-Dobsonian-Reflector-Telescope/dp/B002SCV6P6

    Your own somewhat portable observatory is what that is.  Newtonians require collimation, the alignment of the optical system, perhaps upon arrival and occasionally thereafter on a regular basis.  The telescope is also known, colloquially, as "the best bang for the buck".  They tend to be ready to observe with within 30 minutes or so.  This is a U.S. listing for the Sky-Watcher 8" "Dobsonian"...

    https://www.astronomics.com/sky-watcher-8-f-5-9-classic-200p-dobsonian-reflector.html

    However, that one does not have metal springs for the primary-mirror cell, which would make collimation easier, although the rubber grommets used instead can be replaced with metal springs.

    A Maksutov is something of a specialty, and usually acquired after a run with one or both of the other two.  It has the longest focal-length of any other design, and has been described as being "refractor like" in optical performance.  The design is ideal for medium-to-high powered views of the Moon, the planets, and the double-stars; not to mention quite a few deep-sky objects in addition.  A Maksutov takes the longest to acclimate to the outdoor conditions, and in being ready to observe with in about an hour or so.  Maksutovs require a dew-shield, and may perform best on a go-to mount...

    https://www.amazon.com/Celestron-NexStar-127SLT-Computerized-Telescope/dp/B0038LX8XE/ref=sr_1_3?keywords=celestron+127+slt&qid=1564942467&s=electronics&sr=1-3

    Maksutovs are collimated by the user, but rarely so as they hold their collimation from the factory quite well, and are perhaps the most difficult of the mirrored designs to collimate.

    • Like 2
    • Thanks 1

  14. 20 hours ago, Plumb71 said:

    Thanks for the help, yes i finally ordered a Explorer 150p f5

    Congratulations; you just ordered the one telescope that is the closest to being an all-rounder, with magnifications ranging from a low 19x-23x, and binocular-like, up to 200x and beyond with the aid of 2x and 3x barlows.  I have a 150mm f/5 Newtonian myself.  Keep in mind that for the higher powers the telescope's collimation must be spot-on; and don't fret upon the initial attempts, as you'll get the hang of it in no time.  For all I know, you may already be a whiz at it.


  15. For a ready-made, you will need to measure the diameter of the telescope's white cowling there at the front.  Do not rely on the stated aperture of 150mm as a measurement.  It appears to be the "174-184 mm (150mm Newt):  £68" within this listing...

    https://www.firstlightoptics.com/solar-filters/astrozap-baader-solar-filter.html

    But for peace of mind before placing an order, measure the diameter of the cowling...

    diameter.jpg.c3a85cbd8465cd2260d85509997e75d6.jpg

    You can measure the diameter along the spider-vanes as shown.  Make certain that the diameter is within that of the filter: 174mm to 184mm, and you're good to go.

    As I understand now, you're considering a 150mm f/5 rather.  The same applies nonetheless.


  16. I realise that it's more costly, but in the long run I'd choose the 150P-DS...

    https://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-eq3-2-eq3-pro-goto.html

    You'd get a better, two-speed focusser, for finer focussing, and if you'd like to take photographs with it in future it'll be good to go; a 150P is not suitable for DSLR-astrophotography, although you can manage afocal-photography, and EAA-photography perhaps.

    In so far as collimation...

    https://www.firstlightoptics.com/other-collimation-tools/rigel-aline-collimation-cap.html

    ...and/or a Cheshire...

    https://www.firstlightoptics.com/other-collimation-tools/premium-cheshire-collimating-eyepiece.html


  17. You'll have your best chances for success in detecting galaxies with a 200mm Newtonian, the 200P, of course.  You will need to learn to collimate it, in general, and particularly for the higher powers associated with the Moon and planets; and in the splitting of double-stars, if such is of interest.  To be on the safe side, do look into pulling the kit with a cart or other rather, and instead of carrying it.  Lots of folks make use of that solution for their larger "Dobsonians".

     


  18. 1 minute ago, vlaiv said:

    I forgot flocking, very important thing with some telescope designs (some that use internal baffling are less affected).

    With newtonian design, you want to extend tube (can be blackened cardboard / plastic extension like dew shield) so that focuser is at least 1.5 times diameter of tube from the scope aperture. This again prevents stray light reaching tube walls opposite focuser and improves contrast (although you have flocking and light absorbing paint it is better if light does not reach those places at all).

    In turn, I had forgotten about the dew-shield, in this case a light-shade...

    https://stargazerslounge.com/uploads/monthly_04_2011/post-21419-133877556647.jpg


  19. 2 minutes ago, PlanetGazer said:

    Would love to hear about the arts and crafts that would reduce the effects of Light Pollution

    You want the entire interior of the telescope to be dead to all stray-light, to all reflections, for example...

    153048531_beforeafter2.jpg.effc8b95e28f6aa40007997aaed537e6.jpg

    The inside of that tube was flocked.  This is flocking...

    flocking225.jpg.797bcc04b65706880fa2837b24fa80bf.jpg

    The flocking is self-adhesive.  It's like very low pile carpeting, but for the telescope, and jet-black.  The surface should be glossed before applying the flocking.  It eats light instead of reflecting it, improving the contrast; blacker sky backgrounds, blacker shadows within the craters and other features of the Moon.  Stray light sources include street, porch, security, and automobile lights.  If observing deep-sky objects, the Moon can be a source of stray light as well.

    For those areas inside a telescope that cannot be flocked, those are painted with the flattest and blackest paint available per locale.  For example, these nuts for adjusting the spider-vanes, on the outside of the tube, protrude into the telescope, and were blackened...

    knobs4.jpg.f9c69d42a9a957a65b8c1737da873930.jpg

    In the case of that Newtonian, the only areas that reflect are the mirrors themselves.  External light shields, made from PVC tubing and tarps, and a black drape over the head, like that of yesteryear's photographers, also help to combat light pollution.  Sky-glow however is improved with special filters, or once were.  

     

    • Like 4

  20. On 25/07/2019 at 17:07, cletrac1922 said:

    Hi Guys

    Where I am have Bortle 4

    Further inland, now getting issue with light pollution due to mining and coal seam gas power generation

    Have never looked for double stars

    John

    My skies are at about that, and I haven't really pursued double-stars myself, but that's about to change, and with this...

    Maksutov5b.jpg.72808e2acd7b20dc306b83bb97e1a758.jpg

    ...a 5" Maksutov, and with a 1900mm focal-length; considerably longer than that of a 10" "Dobsonian".   Zowie!  I've only had it out at night once.  Reaching the higher powers for the splitting of double-stars is most readily accomplished with that one, and I'm referring to the physical act of popping this short focal-length eyepiece and that into the focusser; the scaling upwards fluid and butter-smooth, the images sharp and crisp, and all in a compact, ergonomic package. 

    Per the design, a 5" Maksutov is not too small, nor too large, just right rather.  


  21. Hi Daniel.  It's good to hear that you're doing better.  Welcome back. 

    A kit with a go-to mount, the mount would take up the lion's share of the outlay, and with the telescope generally taking a back seat, either in quality or aperture.  Folks prefer a go-to mount if it's difficult for them to find things in the sky, whether due to excessive light-pollution, or if they'd rather not star-hop in the finding of objects with a manual mount.  The basic "Dobsonians" are not upgradeable to go-to as far as I know.  They're also not suited for DSLR astrophotography; only afocal, and perhaps EAA(electronically-assisted astronomy), photography modes.  Research those two types of photography for more information.  Many folks have a lot of fun pursuing both.

    The Baader set of eyepieces and a turret would be allright for a SkyMax 127, although not ideal.  If you like the turret, perhaps you can get that separately and insert other eyepieces; any 1.25" eyepiece would fit.  The 150mm and 200mm "Dobsonians" sport 2" focussers, although you'd probably only get one 2" eyepiece, and for the lowest power possible with the telescope; a 2" 32mm or 38mm.  2", low-power eyepieces can show you a much wider view of the sky, which would help in the hunting and finding of objects, then to insert an eyepiece of higher power, likely a 1.25", and  for a closer look.

    Like happy-kat, I've been wondering the same, as we don't know the exact nature of your condition.  Naturally, a 150mm "Dobsonian" is going to weigh less than a 200mm, and with a smaller aperture, but it's a bright telescope in its own right which would show you a lot.  The Skymax 127 is a 127mm Maksutov, and for medium-to-high powers; less aperture still, but with go-to.  I just got a 127mm Maksutov myself, without go-to, and I'm really looking forward to putting it through its paces.  My skies aren't all that bright at night, except towards the north, nor very dark.   In between I'd say; Bortle-4 if I had to guess.  I couldn't use go-to, as I have far too many trees here at my home, and I don't venture elsewhere to observe.

    Again, welcome back, and let us know what you think.

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.