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TAL 150P


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http://stargazerslou...piter-10th-nov/

The 3rd image is about what I got through my 7.5mm EP for reference. I was hoping I would see a similar image through my EP to the 1st image on the link.

Sent from my Nexus 4 using Tapatalk 2

Using the 1st pic. On my pc keyboard, if I hold down the 'Ctrl' key and click 4 or 5 times on the '-' key, thus reducing the screen size, then that's the scale I'm seeing Jupe at, at about 150x magnification in my scopes. The more you train your eye, observing the planets, the better your brain learns to pick out detail.

Don't let that super pic fool you. That image is made up of loads of pics all stacked on top of each other and using software, 'made' into that one image. No matter how experienced you are, you'll never see a planet as well as in a quality image.

Learn to use averted vision(google it for a far better explanation than I can give). It is quite amazing how much more detail(on any target) can be got this way !!

Andy.

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My lock knob knocking is rubbing against my other knob.......I'm getting advice from my GP.

Sent from my Nexus 4 using Tapatalk 2

Hehe.

Hope you see what I mean though. If you position the two knobs just right, they should slip by each other without bumping against each other.

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Yes I see what you are saying - it is a true shame TAL overlooked this simple mistake.

I suppose I could always take the locking knob out and get a local engineering place to make one longer or cut one down. However if I don't need to fully tighten/turn them I should be ok with the flawed design.

I'm attaching a picture of the counter weight problem so I can try describe it better (my first attempt at describing it was v.poor).

IMG_20130113_223413_zps9a4f2c30.jpg

Looking at this photo maybe I'm been completely simple by not having the counter weights in the right place, the small arrow where the gap is between the top counter weight and the angle adjuster gets very small when angling the scope more towards the horizon. It's very hard for me to get my fingers in and adjust the angle smoothly when there is so little space for my fingers...

I'm looking at EP's now - maybe a 5mm from the range that was pointed out earlier in this thread > http://www.firstlightoptics.com/celestron-eyepieces/celestron-x-cel-lx-eyepiece.html

Are these EP's 1.25" or 2"? I can't find anywhere that says what size they are........if they are 1.25" am I; a) Better suited with a 2" EP B) Need some sort of reducer so I can use 1.25" EP's

Thanks again,

Chris

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Ahha, got you. That wee hand adjuster is a nice new-ish addition to the mount. Older ones don't have them.

I hope the following makes sense, asI have man-flu(according to my other half !) at the mo, so my head is a bit bleargh.

The mount isn't going to be used pointed at the horizon when in use though, only when you're balancing the weights on the shaft, with the scope tube weight. See page 14 of the user manual. So with the DEC shaft(that's the axis with the counterweight bar) horizontal to the ground as in the pic in the manual, loosen the RA(In page 18 of the manual, Tal call it the polar axis. ie: that's the shaft that if it were hollow, should point to polaris/pole star when you're set up) lock/tension knob. If the weights are positioned correctly, you should be able to swing the scope and counterweight shaft to and fro, in perfect balance. Move them to suit. If you have a 'magic marker pen', make a mark on the shaft where the weights sit. That way you won't need to do the balancing thing evertime you set the scope up. Now fully tighten the lock/tension knob, then loosen just enough so that the scope can move by hand. Not too loose, but not too tight.

Next - Still with the scope and DEC axis/arm in the horizontal position, crank the small latitude adjuster until it reaches your latitude. I'm guessing you're about 53 or 54 degrees?? You'll have plenty of room to get your hand on the adjuster, if you do it this way?

Don't forget to balance the tube in it's rings, by loosening the tube rings clamps slightly, loosening the DEC lock/tension knob, and move the scope up or down in it's rings until balance is reached. Tighten the rings back up, then again as above, fully tighten the tension/lock knob, then loosen slightly as before.

That should be you ready to go.

Whilst the following topic was regarding the big MT-2C (for Tal2M) mount, it might offer some helpfull tips for the manual Tal mount??

As always, if any of the above sounds guff, just ask away and I'll try n explain a bit better.

Cheers,

Andy.

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Ahha, got you. That wee hand adjuster is a nice new-ish addition to the mount. Older ones don't have them.

I hope the following makes sense, asI have man-flu(according to my other half !) at the mo, so my head is a bit bleargh.

The mount isn't going to be used pointed at the horizon when in use though, only when you're balancing the weights on the shaft, with the scope tube weight. See page 14 of the user manual. So with the DEC shaft(that's the axis with the counterweight bar) horizontal to the ground as in the pic in the manual, loosen the RA(In page 18 of the manual, Tal call it the polar axis. ie: that's the shaft that if it were hollow, should point to polaris/pole star when you're set up) lock/tension knob. If the weights are positioned correctly, you should be able to swing the scope and counterweight shaft to and fro, in perfect balance. Move them to suit. If you have a 'magic marker pen', make a mark on the shaft where the weights sit. That way you won't need to do the balancing thing evertime you set the scope up. Now fully tighten the lock/tension knob, then loosen just enough so that the scope can move by hand. Not too loose, but not too tight.

Next - Still with the scope and DEC axis/arm in the horizontal position, crank the small latitude adjuster until it reaches your latitude. I'm guessing you're about 53 or 54 degrees?? You'll have plenty of room to get your hand on the adjuster, if you do it this way?

Don't forget to balance the tube in it's rings, by loosening the tube rings clamps slightly, loosening the DEC lock/tension knob, and move the scope up or down in it's rings until balance is reached. Tighten the rings back up, then again as above, fully tighten the tension/lock knob, then loosen slightly as before.

That should be you ready to go.

Whilst the following topic was regarding the big MT-2C (for Tal2M) mount, it might offer some helpfull tips for the manual Tal mount??

http://stargazerslou...e__hl__ tal 2m

As always, if any of the above sounds guff, just ask away and I'll try n explain a bit better.

Cheers,

Andy.

Wowzers! That is some seriously good reading you supplied there AndyH - Just half way through your collimating method with the 35mm film case & pinhole. Very nice indeed!!

Glad work is quiet at the moment, I've got some serious brain scratching to do this afternoon.

p.s - Did you see my question about the 2" and 1.25" EP's. I'm guessing most of the aftermarket EP's available to buy are 1.25" so I need a 2" to 1.25" converter?

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Just checking - You do have the adapter that fits into the top of the focuser? It converts it from 2" inside diameter to 1.25". It's the central item in this pic........

8382537743_2403a079b3_o.jpg

Cheers,

Andy.

hahahaha - I've just slopped coffee down myself. Yes I do have this part on my focuser, and I did wonder why there was an inner piece.......................why did I not just measure one of my EP's, why did I not just use common sense and realise my EP's are not in any way or form 2", right now I feel a danger to society because of my stupidity!!!

It's not my fault, I'm just excited, and when I'm excited I obviously become..............................THICK!

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One of the best and safest method of cleaning a mirror is to put it under a tepid shower with that at it's softest setting if it has one. The worst thing you can do is to try and brush bits off. Some mirror over coatings will take that but it's best to be safe rather than sorry. I can take a long time to remove a heavy film of dust. It's also possible to "wash your hands" with mild hand soap in the spray from the shower to help things along but do leave it for 1/ 2 hr at least after that to make sure that the soap has gone.

Finally to avoid getting water contamination marks on it when it dries ideally flush it with distilled water if possible - de ionised if not. A final wash with Isopropyl alcohol would be a good idea and if you get some of that a couple of swills around with it removes the need for distilled water.. You could also pour some of that onto the surface of the mirror before placing it under the shower and leave it for a while keeping it topped up. The easiest place to get it in a fairly pure form is probably ebay. It's good for gently cleaning eyepieces to with a rather wet teased out cotton bud taking care not to let it run into the lenses. Best to blow loose dust of those 1st with something like this -

http://www.quicktest...aBLOWER#aBLOWER

Once things are this clean dust will blow off for maybe a couple of years. At some point the general muck and grease in the atmosphere builds up and it wont all blow off.

Last time I suggested the shower on here by the way some one was rather pleased with the results. Some one who I sold my 10in dob on the basis that it needed re aluminising told me about it and was also rather pleased with the result. That mirror thanks to leaving at home when I got married had so much dust on it that it didn't reflect at all.

John

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Wowzers! That is some seriously good reading you supplied there AndyH - Just half way through your collimating method with the 35mm film case & pinhole. Very nice indeed!!

Glad work is quiet at the moment, I've got some serious brain scratching to do this afternoon.

p.s - Did you see my question about the 2" and 1.25" EP's. I'm guessing most of the aftermarket EP's available to buy are 1.25" so I need a 2" to 1.25" converter?

That film canister thing is for basic rough collimation. ie: It's easier and more accurate than using just your eye. If you have a cheshire tube, that's the thing to use. But the final check should always be on an out of focus star ring pattern, no matter what method of collimation you use.

Did you get a x2 barlow with the scope? Here's a pic of one at Tal's factory page..........

http://www.npzoptics.ru/catalog/akcessuary_i_zapasnye_chasti_dlya_teleskopov/linzy_barlou/

Andy.

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One of the best and safest method of cleaning a mirror is to put it under a tepid shower with that at it's softest setting if it has one. The worst thing you can do is to try and brush bits off. Some mirror over coatings will take that but it's best to be safe rather than sorry. I can take a long time to remove a heavy film of dust. It's also possible to "wash your hands" with mild hand soap in the spray from the shower to help things along but do leave it for 1/ 2 hr at least after that to make sure that the soap has gone.

Finally to avoid getting water contamination marks on it when it dries ideally flush it with distilled water if possible - de ionised if not. A final wash with Isopropyl alcohol would be a good idea and if you get some of that a couple of swills around with it removes the need for distilled water.. You could also pour some of that onto the surface of the mirror before placing it under the shower and leave it for a while keeping it topped up. The easiest place to get it in a fairly pure form is probably ebay. It's good for gently cleaning eyepieces to with a rather wet teased out cotton bud taking care not to let it run into the lenses. Best to blow loose dust of those 1st with something like this -

http://www.quicktest...aBLOWER#aBLOWER

Once things are this clean dust will blow off for maybe a couple of years. At some point the general muck and grease in the atmosphere builds up and it wont all blow off.

Last time I suggested the shower on here by the way some one was rather pleased with the results. Some one who I sold my 10in dob on the basis that it needed re aluminising told me about it and was also rather pleased with the result. That mirror thanks to leaving at home when I got married had so much dust on it that it didn't reflect at all.

John

-

Good info, John.

I had totally forgotten that I used the shower method on my 80mm Tal 'M' Newts mirror, years back. I never followed up on it, but did wonder where I could get Isopropyl alcohol from. I'll check it out.

Ta,

Andy.

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Chris - As for eyepieces for your 150mm diameter F5 FL750 scope.

Okay here are my own personal thoughts.

In theory I like to have a range of eyepieces that give me the following magnifications.

30x ................. a 25mm eyepiece gets you this mag

75x ................. a 10mm eyepiece gets you this mag

105x ............... a 7mm eyepiece gets you close at 107x

150x ............... a 5mm eyepiece gets you this mag

180x ............... a 4mm eyepiece gets you close at 188x

200x ............... a 3.5mm eyepiece gets you close at 214x

OR

30x ................. a 25mm eyepiece gets you this mag

60x ................. a 12mm eyepiece gets you close at 63x

90x ................. an 8mm eyepiece gets you close at 94x

120x ............... a 6mm eyepiece gets you close at 125x

150x ............... a 5mm eyepiece gets you this mag

180x ............... a 4mm eyepiece gets you close at 188x

210x ............... a 3.5mm eyepiece gets you close at 214x

So. Firstly it depends what eyepieces you already have and if you have a barlow. Remember a barlow multiplies the eyepiece mag by the power it is. So a 2x barlow used with a 94x mag eyepiece turns it into a 188x. Alternately you can divide the focal length of the eyepiece by the power of the barlow, so a x2 barlow used with an 8mm eyepiece turns it into a 4mm. I don't use barlows, but many do, some don't. Be assured the Tal x2 Barlow , if you have one, is good. The 25mm Tal Plossl is very nice, but one day it might be nice to replace it, so that you can take full use of your 2" focuser. Perhaps a 2" barreled 25 or 30mm widefield eyepiece(70 degrees average field of view or more) ? The 7.5mm is a nice plossl, but tight on eye relief. It's a better piece than the Tal 6.3mm. I can tolerate tiny pinprick eye relief but most folks dislike.

I'm don't think I'm going to recommend you an eyepiece, it's just so complex and it depends on your finances. I have weird tastes that may not suit a lot of folk. Plus a discussion on eyepieces could go on for two weeks, end up in a decision, then start again and end up in a different choice. Read up the many threads on SGL regarding eyepieces, ask questions and get as many folks opinions as poss.

Remember, all eyepieces are good. Some, do certain things better than others, but those others may do some things better than them. :grin:

Andy.

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I'm most definitely not posting info on how to select eyepieces on the basis of exit pupils again. In real terms it's the only sensible way to do it. I will mention the book though "How To Make A Telescope" and that it can be downloaded from the internet archive for free. Eyepiece selection is covered under eyepieces and with 6 and 8in scopes doesn't need thinking about really. 10in too but may get a bit stiff at the high mag end, Bigger than that and some backing of is almost bound to be needed at the high mag end in most peoples observing sites due to seeing conditions.

On the other had though people can just buy a topsy turvy massive collection. Many do in the end as I did but after I knew what I was doing.

John

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Just had a wee re-read of my post and have made some alterations, after having a squint at some of my notes over the years.

30x ................. a 25mm eyepiece gets you this mag

75x ................. a 10mm eyepiece gets you this mag * Of the 6 magnifications listed, this one probably gets the least use, if at all.

105x ............... a 7mm eyepiece gets you close at 107x

150x ............... a 5mm eyepiece gets you this mag

180x ............... a 4mm eyepiece gets you close at 188x * Perhaps not essential, but handy if the seeing is not great and the 200x image just breaks down

200x ............... a 3.5mm eyepiece gets you close at 214x

OR

30x ................. a 25mm eyepiece gets you this mag

60x ................. a 12mm eyepiece gets you close at 63x * As with the previous list, this mag probably gets the least use, if at all. I'd happily jump from 30x to 90x.

90x ................. an 8mm eyepiece gets you close at 94x

120x ............... a 6mm eyepiece gets you close at 125x * Would probably skip this and use the 150x instead.

150x ............... a 5mm eyepiece gets you this mag

180x ............... a 4mm eyepiece gets you close at 188x * Perhaps not essential, but handy if the seeing is not great and the 200x image just breaks down

210x ............... a 3.5mm eyepiece gets you close at 214x

You could add higher magnifications if you're into double star work. On your fast/low focal length scope, probably the only way to do that is with a barlow/eyepiece combo.

On any of my scopes I could happily get by with 4 eyepieces somewhere in the range of roughly 30-50x, 80-100x, 130-150x and 180-200x

:smiley:

Edited by AndyH
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As a start for planets and high res moon and that sort of the thing you shouldn't go wrong by getting an eyepiece that gives a magnification that is the same diameter as the scope in mms. In this case 150x so 5mm. Ideally if you want to make the very best out of the scope for that sort of thing a few more round that value such as a 4 and 6mm can be handy but you may find the 4 doesn't improve the view unless the air is very clear and the scopes optics are good. 3mm may well be too much for planets. If some one used those numbers on a 10in they would probably run into problems and have to drop the magnification.

For DSO's another way of looking at it is field of view. The moon is about 1/2 degree diameter which is one useful field to cover, then you might go for 3/4, 1 degree and so on as far as you can go without to big an exit pupil. This is an aspect that the book doesn't cover and would probably finish up with you buying more eyepieces than you really need. The reason for that is that it gets more complicated. For one your scope will give a reasonable quality field of a bit over 1 1/2 degrees that is about 0.85in dia. The book does cover this. Texereau is bound to consider photography for this sort of thing as they are just mostly grey blobs by eye. At that field angle you may notice that the stars at the edge aren't round. If not well you know you can go wider. For a field this big dimensionally you may find a 2in ordinary plossl eyepiece is a cheaper option than a wide field 1 1/4 and is easier and more pleasant to use. I would hope that there is a web calculator around some where that will help with this as the viewing angle capacity of the eyepiece needs including.

Personally I like to have an eyepiece that gives a 6mm exit pupil what ever field size it covers. In this case that needs a magnification of 150/6mm or 25x so would need a 30mm eyepiece. I like this sort of size for browsing around and actually go longer than that. Tal themselves suggest 25mm which gives a 5mm exit pupil. The book would cut you back even further 3.5 to 4mm. These smaller exit pupils do have an advantage in that all of it is more likely to get into your eye. Some people use a hood to get round pupil size problems due to light levels where they observe. It's not particularly dark where I mostly observe and 6mm isn't a problem for me.

I haven't use a SW plossl for some time so have no idea what they are like these days but going on examples I have used in the pasy I would suggest plossls from TeleVue of Vixen. for the planetary stuff in particular. All of them if you can manage it. With eyepieces it does pay to buy once if you can. As to super wide space walk £300+ parts a newtonian doesn't really justify them. I have 2 apo refractors and manage without them other than 2 particular eyepieces that were not that expensive anyway. On both of those scopes there is some point in seeing as much of a 2in field as possible. Your scope is rather good for a newtonian on that score as the truly usable field size tend to get smaller and smaller as the size goes up and also as the F ratio gets faster. Its a swings and roundabout balancing act.

Why Plossl's? If they are done correctly they work rather well with moderately short focal length newtonians.

John

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Thanks again for the added info.

I've been reading about EP's and this one seems a good choice to go for - Celestron X-CEL LX 5mm.

I also need to have a proper look at my TAL Barlow because I can see multiple colours around one edge of the glass, like it has some oily fluid in there somehow.

On a quick side note; Is there a classifieds section on here for members who stick around? (high post-count/membership length)

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Thanks again for the added info.

I've been reading about EP's and this one seems a good choice to go for - Celestron X-CEL LX 5mm.

I also need to have a proper look at my TAL Barlow because I can see multiple colours around one edge of the glass, like it has some oily fluid in there somehow.

On a quick side note; Is there a classifieds section on here for members who stick around? (high post-count/membership length)

Hi Chris.

That range have good reports, from what I've read.

That marking on the edge of the glass sounds very much like the start of the optical cement(the stuff that glues the 2 shaped pieces of glass together to make a doublet lens) de-laminating or breaking down. I have a few eyepieces where this has occured. It looks nasty, but unless it's really bad, it shouldn't affect the views.

Yes, yes & yes :) Can't remember the exact numbers tho.

Andy.

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Collimating is never a waste of time, its paramount to the views, especially with reflectors. TAL dont do center spots but they are easy to slap on.

Read astro babys collimation guide and guide to ceter spotting, its on her website (along with loads of other good stuff)

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