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finding objects with a dobsonian


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as the title suggests what is the normal method for finding stars/nebulae etc.does it involve angles etc or is it a case of know roughly where to look then search using the finder scope?;) question is asked to help in my choice of telescope thanks

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just purely using the red dot finder/ finder scope

there really isnt any special way with a dob- thats the beauty of it

rich

so its just point in the general location then fine tune/search with finderscope?sorry if i sound a little thick i just wonder how you find these objects which are so small and far away:icon_scratch:
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no its not thick ;)

yes thats literally all i do- just find an area of sky where you know the object is located then 'star hop' from one place to the next- for example finding M13 you can find the keystone (four stars in hercules) then make a rough estimate at where the cluster is

it takes some practice, but once you get used to the sky its not too bad

rich

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When I had my dob I found star hopping was the best technique to use with difficult to find objects, with a detailed enough map I found that I knew I was in the right place even if the object was to dim and out of my scopes/sky conditions to see. You may find that the brighter messier objects aren't to difficult spot anyway, so maybe you could start on them and work up to fainter ones ;)

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Don't own a Dob so will not say too much.

Idea is that you have some idea of where the object of your desire is.

Say M108 which is to the "left" of Merek in the plough.

You point the Dob towards Merek, then use the finder to centre merek, then move off a bit to the "left" and if you have moved by the right amount M108 will be in the field of view of the main scope.

You then centre and magnify and nudge the dob bit by bit to follow M108.

The above should be easy. There are worse.;):evil6::mad:

Me, I just align the Meades and tell them to go find.:mad::D:D:D

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If you put your lowest power/widest field eyepiece in the focuser, then there

is more chance of finding the object.

You need not spend a fortune for a low power eyepiece, although less expensive

ones may not match high end models, they are fine for locating objects before

moving to a higher power if necessary.

Regards, Ed.

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  • 2 weeks later...

I am still relatively new to most on here and have two dobs so can hopefully offer advice that will help too. this is especially so as I have a dob which I cannot currently balance - solution in the pipeline - and so cannot use my usual method which I am missing badly on the newer 6" scope I am really gnashing my teeth to use properly! In fact I love dobs so much I have sold my refractor and mount.

Some good advice so far of course. my own 'must buys' for use with most scopes but certainly manually driven dobs is as follows (in rough order of essentialness (OK not a word, I know!!)):

  1. Telrad or Rigel Quikfinder - this will quite literally transform your ability to find things as you can position the scope in almost the right spot. Place it as far up the scope as you can
  2. Right angle finder - preferably a 50mm objective. I recommend the Orion / Skywatcher 9x50mm RACI - it is excellent. This does two things. Prevents severe neck cricking cf. a straight finder. Also, everything is the right way up so in my eyes easier to follow.
  3. Wide field eyepiece, maybe around 30-35mm for the average dob.
  4. Good book eg http://stargazerslounge.com/equipment-reviews/111106-illustrated-guide-astronomical-wonders-first-impressions.html or Turn Left at Orion. Also lots online to download eg Messier Maps and also Stellarium - free software. I prefer books.

My method is Telrad the main closest visible star. This will then be in the optical RA finder. The star hop using the RA finder and the book etc, to the place you think the target should be. Hopefully it's in the scope eyepiece. If not check your placement. If it is, select a suitable eyepiece and away you go!

Hope this helps. :o

Edited by Moonshane
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Agree completely with Moonshane.

I use a good RDF to orient myself - either on a bright star near the target or between two bright stars for objects like M13 or M57 which lie on a line between two. Then I star hop with a 8x50 RACI finder, under reasonably dark sky the brighter Messiers are usually directly visible in the finder. If not, just find a star that's close and use a low-power eyepiece to find the target.

Baader SkySurfer V is the best RDF i've used, but I have a Rigel QuikFinder on my Dob as it's cheaper :o - finder is an Orion 8x50 RACI. At the start of the session I use a bright star to check that they're all aligned - easy to bump the finder while moving the Dob.

Finding things takes a bit of practice, but it's not hard once you get the hang of it. Start with targets that have good markers nearby - at this time of year M57 is easy (between the bright stars beta and gamma Lyrae, which themselves are near Vega), then hop to M56 (between M57 and Albireo). M71 is another easy-to-find object in the arrowhead of Sagitta. M103 is next to delta Cassiopeia. That will give some confidence that you can do it!

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i favour a location method called the geometric method, this involves using a good sky atlas and a telrad (my favoured method) or a red dot finder and locating the target using patterns in the sky. For instance m13 is a tadge over halfway between a straight line between the two stars forming the 'keystone' of hercules.... judge from the skyatlas where you should place the telrad and then just transpose the book image into the sky (using your imagination) im usually on target 90% of the time using this method, its fairly easy when there are landmarks but a bit trickier when the target is in open sky the trick is to translate distances from the book to the sky... good luck!

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I started off star hopping which is great but now have designed a azimuth circle and pointer and use a wixey for altitude settings.

In conjunction with a lap top this has turned out to be extremely accurate finding me loads of little elusive objects.

Check out the DIY section there's loads of mods there to look through.

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I forgot to add (in case you didn't guess!) that for me anyway dobs and good eyepieces are the ultimate way to get maximum aperture (scope) for your money, and great enjoyment (optical quality) and satisfaction in finding things yourself. others may disagree and goto has a lot of fans too.

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My 127 mak is on a goto mount and though I enjoyed using the goto when I first got it, I find now that I prefer star hopping too. Often though, I like to use a pair of 10x50 binos to find things to look at and explore with the scope. I've fitted a 9x50 Orion Optics RA viewfinder to my scope which helps as it's FOV is about the same as my binos. Then I like to look up what I've found.

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thanks for the tips moonshane.have not purchased a scope yet but i,m definitely leaning to a dob on the old adage more light for your bucks.will take your advice into consideration when choosing.btw thanks aswell to everyone else who replied:hello2:

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no worries mate. It is probably worth linking up with Stargazers Lounge - East Midlands Stargazers

they meet up every now and again and I bet there's a few near you that would be willing to let you see their scopes of various types. they are a top bunch of guys.

ps you can now see the for sale section on here having reached 50 posts.

buying used is a great way of saving even more cash eg http://stargazerslounge.com/sale/113081-skywatcher-200p-8-dobsonian.html was a bargain.

Edited by Moonshane
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No problem finding objects with a Telrad, you can use the Telrad charts. If you live in any sort of light pollution area, then go for a 8inch max. Dob. Any larger you'll be letting in plenty of unwelcome light. I've also a scope on an eq mount, it takes a bit of getting used to.

The Dob is the simplest and most enjoyable way.Just sit it down and start looking!

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no worries mate. It is probably worth linking up with Stargazers Lounge - East Midlands Stargazers

they meet up every now and again and I bet there's a few near you that would be willing to let you see their scopes of various types. they are a top bunch of guys.

ps you can now see the for sale section on here having reached 50 posts.

buying used is a great way of saving even more cash eg http://stargazerslounge.com/sale/113081-skywatcher-200p-8-dobsonian.html was a bargain.

got access to the for sale section about 1 hour after this was sold:rolleyes:

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bummer! they come up every now and again so don't panic. just make sure you buy the right one and do try and use one of two first.

BUT the advantage of buying used is that you can often sell for not much less than you paid so there's not really a great risk.

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pretty much made my mind up on a skywatcher 200p skyliner dob.just need to assert myself and ring FLO to order one:D.the price they are offering them at will allow me to spend a little on extras.would have been nice to see one in the for sale section somewhere close for pick up but never mind i can start trolling for the bits and bobs to go with it:p

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Sorry about snapping up John's 200p, but I can resist everything but temptation. :hello2:

The clincher was John being prepared to ship the 'scope, as I am not really in a position to be able to go and collect one, sad to say (missed out on loads of nice 'scopes due to that :) ).

Shane's right though, nice secondhand 'scopes and ancillaries do crop up regularly on SGL. :blob10:

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Sorry about snapping up John's 200p, but I can resist everything but temptation. :hello2:

The clincher was John being prepared to ship the 'scope, as I am not really in a position to be able to go and collect one, sad to say (missed out on loads of nice 'scopes due to that :) ).

Shane's right though, nice secondhand 'scopes and ancillaries do crop up regularly on SGL. :blob10:

hey no probs about the scope:mad:should have been quicker with the posting :p but i know what you mean about the shipping,have a boxster 2 door roadster which limits the size of items i can get in the motor.hope you enjoy the scope and look forward to any observations you may share:hello2:
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