John

This thread is titled "in praise of the AZ-4 mount" - maybe folks who want to knock it should wait for another to come along (or start their own) called "What I don't like about the AZ-4" ?

I'm sure glad that I don't post gear reviews here now

45 minutes ago, Carl Au said:

So I just unscrewed mine this morning and suprise, suprose it's all change inside. I have always cleaned them up inside before to removr the glue like grease. I know this one felt different (I have had a couple of them before) and now I know why. The large teflon rings have gone and been replaced by barings and there is not a drop of glue like grease in sight. They realy were like a mimi dob mounting iside the cluthes before the re-design. I wonder why they did that, they was nothing wrong with them before. 

That's interesting. The ones that I've owned have all used the teflon ring approach. Quite a change if they have moved to using bearings. You would have thought that they might have called it the "Mk II" with a change like that ?

Was yours a new one ?

Great stuff DV !

52 Orionis is a real tough one if the conditions are less than very good. Needs a lot of magnification to I've found !

25 minutes ago, Sunshine said:

Hello folks! I searched for a thread regarding Alt az mounts as i am interested in getting one for my TSA-102, I have a Vixen GP but unless I am imaging planets it is quite heavy with counterweights. Having said that, I was thinking of something like the Porta II but, I hear they are not very steady when using with a scope larger than 80mm. Keep in mind the TSA-102 is a triplet so its around 11.5 Lbs bare, I need something that can manage 12-15 Lbs when considering finder, rings, etc. If i can use my existing 2" SW steel tripod it would be great, I would love to hear some opinions from those who have similar scopes on alt az mounts.

clear skies!

 

The Skytee II / TS AZ5 mentioned earlier in this thread would do the job for you. My ED120 F/7.5 weighs around 15 lbs all up and the Skytee II handles it well without the need of a counterweight. Not the most sophisticated mount but it's robust and effective.

You will need an EQ5 / HEQ5 compatible tripod - if your SW 2" is that fitting then you are all set.

1 hour ago, callisto said:

A nice Atlas recommended by Mark at Beaufort 

 

 

Mark

Excellent choice - my copy is heavily used.

I love the way the authors invite you to question how things were formed and why they might be as they are. Takes you on a real voyage of discovery !

4 hours ago, Kon said:

@John and @Nik271 with my Dob I managed to see the star ENE for the first time last night just above the diffraction spike as in my sketch. I can regularly see the WSW star. Would the diffraction spikes from the spider vanes make it nearly impossible to see it? Is it worth keep going?

Can you rotate the tube of your scope so that the diffraction spikes are at a different angle ?

1 hour ago, A McEwan said:

Just a diagonal for me. Well, a Baader Zeiss prism (BBHS) T-2 diagonal body which I'll be using in all my refractors from now on. It arrived with mist as well as clouds!

Ant

Excellent diagonal - I use one with my FC100-DL

38 minutes ago, Pixies said:

Not sure about the SW, but when tightening the Bresser lock screws, it effects the collimation. So keep checking as you finish off and use it like a final fine-tuning.

I've found this with a few newtonian primary cell designs. I leave the lock screws undone on my 12 inch dob now, unless it's going in the car somewhere.

There are two faint stars near Sirius that I've found quite important to being able to have a chance to see the Pup star itself. I have circled them in my sketch below (refractor view). One is the one that @Nik271 refers to in his post above. If you can see these two, you have a shout at seeing the Pup star, when the glare of Sirius A is at a minimum.

Over the years I have tried filters, using the field stop edge and occulting bars but eventually it was just looking carefully under the better seeing conditions using a magnification that gave a decent image scale (250x or thereabouts seems to be good) that did the trick. As I've become more accustomed to spotting the Pup star and as the gap between it and Sirius A has gradually opened up, I've been able to see it with smaller apertures. I managed some brief glimpses of the Pup with my 100mm refractor a couple of nights ago. Rather fleeting though. If I did not know what I was looking for, I would have missed them. 

6 minutes ago, Kon said:

Thanks, very helpful! So the star I saw at my E is not the one; I had not seen that one last time so it got me all excited. I did not realise that the separation is not that great and I spent time ignoring what was going on next to Sirius A.

The separation is 11 arc seconds. You can use the separation between Rigel A and B as a rough guide to the "scale" in the eyepiece - the separation there is 9.7 arc seconds but Rigel B is on the other side.

The glare from Sirius usually extends around 10 arc seconds or more around the star, so Sirius B has to shine (well, glimmer) though that.

20 minutes ago, Kon said:

After a couple of unsuccessful tries, I think i may have seen the Pup tonight. I was out around 830 before the moon came up. It was the first night that Sirius did not look like disco lights. It seemed whiter with less colours around it. Using my 8mm BST on an 8" Dob I saw the bright Sirius A with a faint star coming in and out. I could see a faint 'dot' just above the diffraction line towards the East. I spent a good 30 min observing it and the tiny dot Pup was following Sirius as it was getting out of my view. In my excitement I ran back in the house to pick up a scrap piece of paper and made a quick sketch as seen in my EP (sorry if it is not very accurate; the cross hair represent the diffraction lines). By 915-930 some light haze was coming in and sirius was dancing all over again.  Is that it?

Hi,

I recognize most of your stars. I've rotated the sketch that I made with my 120 refractor to match the orientation of yours and arrowed Sirius B. Hope that helps a bit ?:

That part of the UK had a notable meteorite fall a few many years ago. The Aldsworth meteorite fell at 4:30 pm on 4th August 1835:

http://www.meteoritehistory.info/UKIRELAND/ENGL.HTM#aldsw

It will be interesting to see if anybody finds a fragment of this latest fall.

2 hours ago, Stu said:

Cloudy here now  

Well it looked OK here earlier but went downhill quite fast - about as long as it took the 130 triplet to cool down

Still, I've had quit a few nights in a row when I've been able to observe so a break won't do any harm.

I was in a similar position back in 2016. I don't image so I was looking for a "lifetime" visual scope and already had a decent 12 inch dobsonian so went for a refractor. I was dithering between a Tele Vue NP101 and a Takahashi FC100. I already had a nice and quite fast Vixen ED 102mm so I was attracted to the Tak FC100-DL which was made in limited numbers at F/9. The one I purchased was one of the last of the first run of these that was available in the UK at that time. No regrets at all about the purchase.

Having some budget left over, I did then go on to find a 2nd "lifetime" refractor which I could not resist - a TMB/LZOS 130mm F/9.2 triplet which have a bit of a reputation.

So I ended up with a "2 for 1" lifetime scope deal !

I think the TSA 120 that you mention stands out to me as an exceptional refractor, certainly for visual. I'm no imager but it would seem to have a lot of potential in that area as well. 

There is certainly something about the history and culture of the company and their way of doing things that makes ownership of one of their instruments very appealing.

Have fun working through the options

37 minutes ago, niallk said:

I find it difficult to visualise how these were formed, not to mention the ejecta patterns: I've read about possibly a low angle impact & a ricochet. 

Anyone have a link to a video or something which does a good job of illustrating how they may have formed?? I'd be really interested to see it! 

This interpretation is 10 years old so thinking might have moved on:

2 minutes ago, Dantooine said:

That’s one in each pocket and one in the telescope. Need a big pocket for the 21 though 😉

And braces !!!

I bring them in and let them warm up with the caps off.

26 minutes ago, HollyHound said:

Thanks. I've read various posts (yours included) that indicate the same, and indeed TeleVue talk about the sets of 21, 13, 8 or 17, 10, 6... so after playing with just the 21 and 13 over the last few nights in my 10" dob, I'm convinced I should be able to manage with just these three for most of my viewing in that scope... switch to XWs for anything else 👍

I've also got a couple of Hyperion 2" extension rings, so that I can keep them all as 2" eyepieces, which will also help in a session... just need to work out if I need to adjust the Paracorr now for those 🤔

It's funny how you can happily get by with fewer focal lengths when you use 100 degree eyepieces. I'm not quite sure why it is, but that is how I've found it

Probably just as well, given the cost of the things !

9 minutes ago, HollyHound said:

Oh and the final piece of my new Ethos trilogy... the Ethos 8mm... so I can now go 21, 13 and 8 👍

Congratulations on the Ethos 8mm. It's one that I use very often with my 12 inch dob. It gives 199x in that and still shows half a degree of sky

I've often said that I skip straight from 21mm, over the 17mm focal length, to 13mm, but in all honesty the "skip" is quite often straight to the 8mm.

3 minutes ago, Stu said:

I love these two, and enjoy seeing them at different illuminations as they can look very different (as does every lunar feature I guess!) They certainly have been catching my eye the last few nights 

Should be nicely illuminated tonight as well

Forecast is clear here until around 1:00 am I think.

Here is an Apollo 11 photo of the pair:

Nice write up Carl

I agree that the AZ-4 is a very capable mount for a reasonable price.

I didn't use the panning handle on mine either. I found that I used to knock it in the dark as I put my eye to the eyepiece of my refractor. It nearly gave me a black eye on one occasion !

5 hours ago, maw lod qan said:

Yes, incredible image from long ago!

Thanks for posting the link.

Is it just me, or does the one side of the LM look pretty beat up?

I have to think in almost zero gravity on the Moon, that initial jump when the ascent engine fired would be something!

It is not just you - there is some damage to the outer cladding of the LM in that photo. I need to try and find out a bit more about how that came about.

He is certainly not a person to "rest on his laurels" as they say.

Just what is needed to keep the company at the top - keep pushing the boundaries

These 5 inch refractors are mouthwatering

Here is another in action at night but, alas, it's not mine. This is Sir Patrick Moore's 5 inch Cooke refractor. A scope which I found instantly appealing the moment I saw my first photo of it many years ago:

The influence that the above scope had on me has undoubtedly led to the TMB/LZOS 130 that I currently own, below on a GP DX mount. The closest I've come to owning something like Sir Patrick's Cooke. The GP DX was right at it's limit with this F/9.2 refractor:

3 hours ago, mikeDnight said:

..... in studying it I saw things I wouldn't normally have seen.  

And there's the joy of it