mikeDnight

A glorious vintage vixen is definitely a thing of beauty to me Vin. Im sure your dad loved it with all his heart, and im pretty certain you will to.

That's a really nice package! A very nice rich field scope, and to include a mount that has to be more suitable than the AZ3 has to be a good thing.

I've not seen that one before Chris. Is it a renamed star travel or a new ED? Looks very nice!!!!!☺

I think there are quite a few different designs of ironing chairs, so it's worth googling them. Personally I like a bit more comfort as I find my back complaining much more these days. This is my alternative to an official observing chair. It's a hydraulic draughtsmans chair and gives good back support. It cost me £10 at a garden centre office furniture sale about 9 years ago. Very comfy for long observing sessions! 😊

As already stated, they may be the same scope. However, the TS model really emphasizes the use of lanthanum glass as the mating element, but the Starwave write-up mentions nothing about lanthanum. It may be worth enquiring to see if the Starwave uses the FPL53 and a lanthanum mating element. Both will doubtless be good refractors, but every little helps, so if lanthanum is used in one and not the other I'd be inclined to go for the lanthanum version. Would it make any difference in real terms? Possibly not, until you start using higher powers, then the lanthanum may just give a small advantage. Having said that, I've used old ED scopes by Vixen that use neither FPL53 or lanthanum and they've been absoloutly stunning.

I ordered this beautiful Baader Zeiss 1.25" BBHS prism a few days ago from FLO, and Mr postman delivered it this morning. I've already seen an impressive improvement over the Takahashi prism by viewing detail in a random stone wall on a hillside across the other side of town (through double glazing), that was very high contrast and razor sharp in the BBHS but soft and lacking some contrast in the Tak prism. That's not to say the Tak isn't a good prism, it is, but the BBHS looks to be in another league. I've seen great things using the Tak prism, but I'm hoping to see even more through this one. Along with the prism I ordered a Baader helical micro focuser, which is a beautiful piece of engineering and at a fraction of the price of anyother micro focuser option I know of. And also a 2" nose for the diagonal to cut down on adapters. Very pleased!! I did shop around initially to see who had this BBHS prism in stock. It was only Steve at FLO who got back to me with assistance and meaningful answers to my questions. Others seemed indifferent! Thanks Steve, it meant a lot and was very helpful!

That's a superb sketch of M13 that I really can't fault. Your hand writing is good too! ☺ I just turned your sketch into negative on my tablet photo editor and it looks great. I hope you'll post more sketches in weeks to come. Excellent!

While observing a few double stars last night, my RA drive decided it had had enough, so I called it a night. But before that happened I managed three observations of three beautiful doubles.

As the sun drops behind the trees to my west, i cant resist looking at Venus against a blue sky as it gets thinner and larger. Attached are yesterday's observations.

Izar last night in my nearly 4" refractor.

Thanks for that John. I might try this option as im unlikely to find the vixen drive anytime soon. 😊

Thanks Stu, I have two Vixen RA motors and one Vixen Dec motor, but only one controller. Although the motors run, the controller doesn't seem to work, so I'm assuming its the controller at fault. I bought the enhanced RA & Dec drive system by Skywatcher to replace the Vixen drives, and although everything initially worked fine, the "enhanced" controller internally is the nastiest piece of junk I've ever seen. I'll try and find a replacement Vixen hand control to see if the motors are ok, which I presume they are. I'd be happy with just an RA drive if that's all that's available. I'll have a look around and see what's available.

I was out this evening looking at a few binary stars when my RA drive stopped tracking. It's the shabbily made SW red controller that's the problem. It's less than 18 months old and this is the second time its let me down. I do not want to give up my manual control option so go-to is not an option. All I'm looking for is a trustworthy RA or RA & Dec drive. I don't want anything that has a nasty cheaply made Chinese origin. So what im looking for is anyone who can manufacture a reliable drive and hand controller for a Vixen GP / GPDX, either professional or amateur?

Nice image Peter! To ease the frustration of finding Venus against a bright sky, I find using a straight edge such as the edge of a card, or the edge of a roofline helps. It not only gives you a hard edge to scan along, moving it or your position to scan up and down a section of sky before moving on to the next, but it also helps with maintaining your eyes focus, and blocks some of the sky blinding effect of a bright sky. It always seems to work for me, so it's worth giving it a try.

They should bring back those sudden power cuts I had as a child in the 60s & 70s? I loved them!

No Chris, she hasn't! In fact yesterday afternoon a little incident occured after my son's thought it would be funny to remove my tube assembly from its mount in the dining room. They purposely engaged me in pointless conversation, which in itself lead me to believe they were up to no good. Eventually they both cracked up laughing as they pointed to the DX mount standing there with an empty coke bottle in the Tak tube clamp, and stating I'd "make a rubbish detective!" I severely threatened their lives for touching my scope, but they are both bigger than me and weren't worried in the slightest by my threat. When I retrieved the scope from its hiding place, Chrissy my wife came to see what the commotion and hysterical laughter was all about. I walked right past her while carrying the new scope and she didn't notice any difference. Instead she came to my defence and laid the law down to the lad's. They are scared of their mum! So it's official - I've got away with it!! I think!

Does the Sky Tee have a counterweight arm Chris? If so you could construct a Hargreaves Strut extending from behind the lens cell to the end of the counter arm, which should add some stability to the 4" F13. Ive a real soft spot for the Vixen 102mm F13. I had one for years and loved it!

If you have a Ronchi eyepiece you can aim your scope at a bright star, alter the focus until you have five lines or less, and if the lines are straight you've got a well figured lens. If there is any appreciable curvature to the lines you're either over or under corrected and will suffer from SA. A bug comb held at the open draw tube can also act as a Ronchi grating to give a good indication of lens figure too! Find a bright star, remove the eyepiece, then hold the comb flat against the draw tube rack the focuser in or out until the light from the star floods the field. You'll se the black Ronchi lines that will give you a good idea of the figure. If the lines are wedge shaped, you're out of colimation. I've used a number of well figured Chinese achromat's, but I've also seen a lot that are sub standard. If the lens has SA then I'd return the scope as its not fit for purpose. Even in a short achromat the star images should be sharp, although there will be some CA around bright stars. But if the scope has SA its star images will have an annoying blur affecting the diffraction rings as well as contrast and definition.

A telescope of say 8" will always gather the same amount of light no matter what eyepiece is used. If however you fit an adjustable diaphragm at any point throughout the system, thereby cutting into the light path, you are effectively reducing the aperture, even though the true aperture of the instrument remains 8". Because of the diaphragm it is unable to work at its full aperture. An eyepiece that has a 10mm exit pupil will still deliver a full aperture view, its just that the human eye can't accept that exit pupil size. In the same way, the human iris is just such a diaphragm, which can cut into the light path if the max 7mm limit is exceeded.

To be honest, I've always felt that trying to filter out CA detracts from the cleanness of the view. CA is the nature of the beast and not a fault, so it's best to view the 4" F5 achromat as a specialist instrument. It's specialism being wide star fields, ideal as a comet seeker.

By using an eyepiece that gives you say an 8mm exit pupil, an iris that has a maximum 7mm aperture will be cutting into the light path, effectively reducing the aperture of the scope. However, you can still use an oversized exit pupil if the eyepiece frames the picture well, you just won't be using your full aperture. But you can only do this with unobstructed systems such as refractors, as the secondary obstruction becomes problematic with reflectors. Al Nagler explains it perfectly if you fancy searching Televue's site. The real problem with very low powers, even if the exit pupil doesn't cut exceed 7mm, is that the sky brightness lacks contrast. It's better to increase the power in most cases so as to darken the sky background, and there by increasing contrast.

I could do a calendar of SGT caricatures for 2021. That would be one sure way of making enemies, as everyone can see how each caricature resembles the other person, but not their own. Of course I would never intend offence, but it never seems to stop it being taken. I only ever focus on a person's more endearing features! 👃👂👀

Thanks for everyone's input on this thread. Its made things a little more understandable now I know green stars don't exist in reality, but do exist as a contrast effect. It's also comforting to know I'm not the only one with odd eyes.

Thanks Stu, I'm just going to have to come to terms with having odd eyes as regards colour. Perhaps my left eye gives the true colour, as the Castor binary both appear as brilliant white, but its my right eye that's stronger and better suited to detecting ultra-fine detail. Perhaps this colour perception issue is why some see Mars as being yellow orchar, but I've only ever seen it as being varying shades of pink. I have heard years ago, but can't remember from where, that female astronomers have better true colour perception than us chaps, due to some genetic advantage presumably. Perhaps we could encourage the girls on SGL to check out a few contrasting doubles just to see if there's any truth in that claim?

Is that actually factual Stu? I too have seen green stars, always as less bright companion stars, but I thought they were rare not non-existent.