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.

stargazine_ep34_banner.thumb.jpg.28dd32d9305c7de9b6591e6bf6600b27.jpg

gnomus

Telrad Placement (Where On Earth is M81 - Part II)

Recommended Posts

In my 'first light' thread (https://stargazerslounge.com/topic/266571-where-on-earth-is-m81/#comment-2920432), a number of people suggested I should fit a Telrad to help with finding objects.  The question is: where should I put it.

When I first got my (first) Dob I set things out like this:

reddot2.jpg

This allowed me to move my head from eyepiece to Red Dot to finderscope with relative ease.  

So I went looking for pictures of 'folks and their Dobs'.  It seems most people set out things rather differently to what I did.  In the thread 'Telrad Placement On a Dob' https://stargazerslounge.com/topic/196058-telrad-placement-on-a-dob/ I found a photo that seemed typical:

post-22147-0-73812700-1380517932.jpg

 So before attaching my Telrad I thought I'd try out the 'correct' placement with my Red Dot - as so:

reddot1.jpg

However, in the field I found this very difficult to use.  It was quite a stretch to get my head behind the Red Dot finder, especially when half way up a ladder.  So I'm a little stumped - it seems to me that if I put the Telrad as in photo 1, it could interfere with my ability to get to the eyepiece and focus, especially if I put it on a riser rail.  In position 2, however, I am going to struggle to get my head round the scope to see through the thing.  Apologies for my utter lack of knowledge of matters Dobsonian, but does anyone have any suggestions?  I am wondering if something like this would be a good idea: http://www.scopestuff.com/ss_telo.htm  In position 1 this would bring the Telrad forward of the eyepiece and would allow me to simply dip my head a little to see through it.  Does anyone know if something similar is available in the UK?

Incidentally, despite the problem getting my head behind the red dot we had a great 'second light'.  We revisited some of our successes from night one, including; Jupiter; Owl Cluster; Double Cluster; M42; M35; M36; M37; M38; and M51 - finding all of these quite easily.  But we also looked for some other objects.  I found M65 and M66 (but not the third part of the triplet).  We also spotted M95, M96, M105 and NGC3371.  And in Cassiopeia we found NGC663 (I think) and M103 (for sure).  M103 was sensational - almost as good as the Owl Cluster.

To finish I thought I'd have a go at M13.  I found it at first attempt.  The combination of scope and eyepiece gave a terrific view.  I may have said 'Wow' out loud.  What a magnificent object.  I had seen it before but not nearly as distinctly as this.  It appeared as a sort of large granular ball studded with a myriad of individual stars (jings I'm getting a bit 'flowery' now - best to nip that in the bud).  

Last night was certainly better seeing than night one - or perhaps we simply obtained a better collimation.

Any thoughts on where I could stick the Telrad ('Ooh Er Missus .... No', as Frankie Howerd might say) would be most welcome. 

[EDIT: I should add that we failed again on M81 M82.  The scope was pointing almost straight up and was a little awkward to manipulate from up the ladder, especially as it was on a small piece of plywood that I hadn't got anywhere near level.  Also getting my head behind the red dot in position 2 was almost impossible.  I am ashamed to report that I couldn't find M78 either :blush:]

Edited by gnomus

Share this post


Link to post
Share on other sites

Other considerations (storage) might apply but it could, in principle, go on a slightly extended arm forward of the front of the scope and to one side of the EP, making for a short movement of the head between the two. This might men adding a little weight at the bottom.

Olly

Share this post


Link to post
Share on other sites
2 minutes ago, ollypenrice said:

Other considerations (storage) might apply but it could, in principle, go on a slightly extended arm forward of the front of the scope and to one side of the EP, making for a short movement of the head between the two. This might men adding a little weight at the bottom.

Olly

Are you thinking about something like a small piece of plywood attached to the front rim?  (I don't think balance would be a problem - the Telrad is lighter than the red dot - and storage is not an issue.)

Share this post


Link to post
Share on other sites

The ideal place for the Telrad is between the 9x50 RACI finder and the focuser. The optical finder can have it's eyepiece angled for ease of access but the Telrad (Rigel Quikfinder in my case) needs to be looked through square on.

On your scope I'd move the optical finder out to where the Baader finder is in the 3rd photo above and put a Telrad between it and the focuser.

 

Edited by John

Share this post


Link to post
Share on other sites
2 minutes ago, John said:

The ideal place for the Telrad is between the 9x50 RACI finder and the focuser. The optical finder can have it's eyepiece angled for ease of access but the Telrad (Rigel Quikfinder in my case) needs to be looked through square on.

On your scope I'd move the optical finder out to where the Baader finder is in the 3rd photo above and put a Telrad between it and the focuser.

 

You can't see it in the photos, but the RACI is slotted into a Synta shoe that is on a metal platform that comes out from (and is bolted underneath) the focusser, so that the platform is an inch or so above the wall of the Dob.  The only way to get a Telrad there (short of taking the focusser off to remove the platform) would be to get a Synta adapter of some sort, like the one I linked to.

Share this post


Link to post
Share on other sites
17 minutes ago, gnomus said:

You can't see it in the photos, but the RACI is slotted into a Synta shoe that is on a metal platform that comes out from (and is bolted underneath) the focusser, so that the platform is an inch or so above the wall of the Dob.  The only way to get a Telrad there (short of taking the focusser off to remove the platform) would be to get a Synta adapter of some sort, like the one I linked to.

I have the same focuser on my dob. The metal platform will be an add-on and could be removed I'd have thought ?. Or you could fit a Rigel Quikfinder base onto it - they work pretty much as well as Telrads do.

I find you need to minimise the distance you need to move your head / eye between the two finders and the eyepiece.

 

Edited by John

Share this post


Link to post
Share on other sites
57 minutes ago, gnomus said:

Are you thinking about something like a small piece of plywood attached to the front rim?  (I don't think balance would be a problem - the Telrad is lighter than the red dot - and storage is not an issue.)

That was my thought but the others make valid points (though I'm the kind of person who needs to 'see' things before I can get much of a grasp.)

Olly

Share this post


Link to post
Share on other sites

When I had a 12" flextube, I removed the finder scope bracket and fixed my Telrad to this position. I included a 2" raiser base  permitting comfortable use. At this time I was happy using only the Telrad combined with low power wide field e.p's and since the scope was a little top heavy, not having the finder scope attached assisted with balance. 

Since I have been using a 14" dob, I like to combine both Finder scope and Telrad for locating objects and conversely the scope is a little bottom heavy, so helpful again in this regard. I to had a  bit of a dilemma as to where best to place the Telrad and decided as your pictures illustrate, going along with general consensus, that it ought be placed alongside the finder scope and not necessarily in-between this and the focuser. I now use a 4" raiser base and this helps when leaning across and I have become accustom to this placement, however I have a spare Telrad base and may consider fixing it temporarily at least alongside the focuser and trial this as this would have been my original preferred option.

Therefore a 4" raiser base is a worth while investment and trial the position temporarily, fixing the base with PVC electrical tape to you feel confident as to what works best.

 

 

Share this post


Link to post
Share on other sites

I've been in touch with Jim at Scopestuff.  It seems that his adapter will allow me to mount the Telrad in the 'position 1' synta dovetail and will result in the Telrad sticking out in front of the scope a tad.  I think this should work quite well.  I may need a riser rail but I will wait for the adapter to get here before deciding.

I'll let you know how I get on.

Thanks everyone for their thoughts.

Share this post


Link to post
Share on other sites
5 hours ago, gnomus said:

I'm getting a bit 'flowery' now - best to nip that in the bud

<GROAN>

Share this post


Link to post
Share on other sites
8 minutes ago, Stub Mandrel said:

<GROAN>

I'm here all week ........ Probably.

Share this post


Link to post
Share on other sites

Keep trying re M81/82 - you'll get there.  As it happens I tried Olly's hop to it last night as I've always found it more difficult than it should be to track down.  The hope worked a treat, but up there in what some call the "Dob Hole" (overhead) it can be difficuilt to move around in the right direction.

Paul

Share this post


Link to post
Share on other sites

Quick follow-up and related question to Gnomus'  original post:

I've now taken delivery of my Telrad and RACI.  They look great on the dob.  But I currently have the Telrad sandwiched between the RACI and the focusser.  This is really comfortable and easy but I can see that the Telrad will get very easily fogged up unless I hold my breath when using the RACI.  I don't fancy doing that because my wife would be really cross if I didn't come back from an observing session because I've passed out.

What do the rest of you do?

Paul

Share this post


Link to post
Share on other sites

Hi, congrats on the scope - do I recognise that as the Lukehurst with a Zambuto? I thought it looked like a beautiful instrument :)

Here's where the Telrad is on my dob - but I've opted to skip the frac finder, and now completely cheat with AN!  On my 10", I have the Telrad in the same position as in the SW flextube pic above, but it's not the best spot tbh.

IMG_20151207_215013311.jpg

The way I find M81 (without cheating with electronics) is to follow a diagonal line across the 'saucepan pot' of the Plough, and continue on out an equal distance. M81/82 is a smidgen off to one side of this, and I usually can get them with just the Telrad to position the scope with my lowest power EP.

  • Like 1

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...

Important Information

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