Posts Made By: tim wetherell

Hi.

I'm thinking of investing in a 26mm type 5 nagler. I've had a few naglers over the years and found them great - except for the 17mm type IV. Lovely eyepiece but for my eyes and scope I found the kidney beaning blackouts a real problem. The 16 type five I replaced it with was just fine though. Does anyone have experience with blackouts in the 26?

My reasoning is that if a 16 type 5 is good a 26 type five should also be fine right? Or am I oversimplifying things? :S

Thanks

Tim

Any of you guys know where there's a current finder chart (or photo) for pluto that goes down to mag 14 or 15? I'm trying to see it with a 5.5" refractor which is really pushing it I know. I can see all the mag 12 stars on my chart no problem and there are other "averted vision" dots in amongst them but I've no idea which one is pluto. It's hard to use the movement method cos these are right at the very, very edge of perception so I can't sketch them accurately. I figure if I knew when pluto was near a mag 12 star and that there were no other faint stars around I'd have him!

I managed to see the quasar 3c273 with this scope no sweat at all, but I had someone's astrophotograph to go on that showed stars many magnitudes fainter. if any of you guys have a photo of pluto from the last week or so that would be a great help too

all the best

Tim

Hi everyone,

hope this is the right forum to ask this. Does anyone know of a book they could recommend on double stars? What I'm after is a book that lists the doubles in each constellation with their magnitudes and separations? Lots of books contain bits of this info but I've never seen one that had it all?

all the best

Tim

Thanks for the earlier advice on Pluto charts and hunting down this elusive little former planet. I'm happy to say that after quite a struggle I did manage to see it in my 5.5" refractor under reasonable but not pristine skys (about mag 5 outer suburban).

Step one was making up a crude astrophotography rig, nikon coolpix 5000 pointing down a 30mm 2" eyepiece. With this and my less than perfect clock drive I was able to make a 1min exposure that recorded stars down to about mag 14. When overlaid on the excellent Sky and Telescope finder chart, this showed me where the fainter stars were, extending the chart to maybe mag 14 or 14.5.

Then I took photos on a second night to ensure that I could record Pluto, and sure enough, the little trail was right where S&T said it would be. OK, it should be a spot not a trail - hotshot astrophotographers please don't laugh at me

Then on night 3, I set out to look for it visually, knowing exactly where to expect it. With averted vision it was possible to make out the faintest of specks about 30% of the time. Not sure why not 100% perhaps varying seeing or perhaps my retina has bits that work better than others? Having sketched the observed position on the chart I then took a photo to confirm. When overlaid on the computer afterwards, the match was pretty much perfect! 8)

You would never in a million years find Pluto in a 5.5" if you didn't know exactly where and when to look, but I'm happy to say I was able to do it!

I've read an account of a guy doing this in a 6" refractor too and he mentioned Pluto being visible for less than 100% of the time. Does anyone have any ideas why this is?

all the best

Tim

Hi everyone

Noticed that pentax have a new (well new to me!) XO 2.5mm eyepiece. Anyone used one and/or have any thoughts on them? Couldn't find a review on line.

all the best

Tim

Hi Everyone. I'm building an 8" f9 refractor and want a wide field eyepiece option. I'm happy to go with larger than the standard barrel (and the physics dictates I must 8O ) so have been looking at options. Has anyone her ever seen or used one of Harry Siebert's 2.7" or 3" EPs?

I've had some of Harry's other EPs and they've been good but never seen one of these - I guess they're rare beasts!

all the best

Tim

hi Doug

sounds like you've picked out some sensible options. I've had very positive experiences with the UO HD 7mm ortho. I find these are very sharp and have excellent throughput. i also have a couple of starsplitters in the very short focal lengths which perform exceptionally too. My experience is that the UO has fractionally better contrast but the starsplitters are very sharp and have better eye relief. both are superb performers and IMHO some of the best value for money available.

all the best

Tim

I'm jealous - the Australian supply is still chugging its way across the pacific!

hi Marc, yes you must be the guy just behind me in the line to win lotto! I'm gonna spend mine on a custom 9" f9 apo

It's probably not what your bank account wants to hear, but the 13mm ethos really is something else. It's not just the field of view, it's the accessibility of that field. In other words there's no little eye hole to squint into, it's like looking through a window. Also as others have said, for a given true field of view the extra magnification darkens the sky and coupled with the excellent contrast of the ethos, the experience is breathtaking! They are big and bulky though, fine for a TV refractor but maybe more of a problem on a finely balanced dob.

My experience has been that I hardly ever need anything between my TMB 40mm and the Ethos 13. It sounds like a massive gap but the true FOV range isn't nearly as big as it sounds. 2.7° to 1.4° in my scope so it's like having a 20mm of the same design as your 40.

all the best

Tim

Hi

Dan's link shows the accurate way. I have an quick, rough and dirty way too

http://www.astromart.com/forums/viewpost.asp?forum_post_id=604520&poll_id=&news_id=&page=3

My experience has also been that it can vary. The ones that are often very different to advertised are those with a built in barlow. I think that in this case it's not that the design or manufacture is inaccurate, it's that how far down your optical chain it will sit at focus depends on the focal length of your scope. So what might be a 5mm in a 1000mm scope might be a 5.3mm in a 300mm scope.

I've often wondered what the experience of binoviewing people was on variable FL. The barlow issue wouldn't matter as it would be the same for both paths but presumably a 5% variation in the native FL would be a really big deal in that situation?

all the best

Tim