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johnha

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About johnha

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    Lancashire
  1. Thanks for all the replies and comments - they have all been really helpful. In the end I've bought a Celestron NexStar 4se (102mm Mak on an AZ GOTO), the reasoning being: 1) The mount offers more alignment options, includes a basic wedge and supports EQ alignment. 2) It was available locally (important as my ability to receive large boxes is limited) although I had underestimated the size of the box such a 'small' scope requires. 3) Although the SkyMax offers a larger aperture - I reasoned that the actual difference would be limited (given the longer focal length of the SkyMax). Apart from a minor hiccup (requiring a firmware update for the hand controller), so far I'm really pleased with the package - the GOTO (and it's various fine tuning options) is really interesting. Thanks again, John.
  2. I'm just renewing my interest, and as such, don't have a wealth of experience to help, but from a 'beginner' aspect I'd mention the following (this is my experience, your mileage may vary based on budget, space, time & motivation etc.): Make sure you know how big/cumbersome your intended purchase really is and whether you have somewhere convenient (for frequent observing) to keep it. I have a 4.5" f=900 newt and the box it came in was much bigger than I anticipated, storing it for frequent observing was such a pain I put it back in the attic for a couple of years. I know someone who bought an 8" SCT + power tank but hadn't taken it out of the box for months - he bought it for visiting 'dark sites' but never found the time (or had the motivation). I'm looking for a lighter, more portable (and easier to store) package to re-boot my enthusiasm and understand my preferences so I'm better informed about a bigger, more serious set-up later. Remember that 'set-up' (and packing away) time eats into your observing time, the more critical it gets the longer it takes. I have drastically improved mine in the last week or so (10 mins last night for ten mins of Jupiter before thick cloud rolled in). I originally thought I needed an EQ-5 & pole finder as a minimum but that would be bigger, heavier and take longer for me to set-up - my approximate alignment with Polaris centred in the field of view seems to work for me. My mount has problems (gear slop, clamps loosening etc.) but they're not as critical as I first thought - and expecting the next mount up to be significantly better & precise might be a mistake. I'm a serious photo enthusiast and envy the excellent images the AP guys achieve, but I realise that requires another level of everything - knowledge, experience, scope, mount, alignment, guiding, filtering, tweaking, shooting, stacking, processing & time etc. etc. You could start with top-spec mount suitable for that but it would likely be much heavier, cumbersome and awkward until you're able to put it to that use. I've been thinking round the newt, dob, Mak, refractor loop several times, each time there's a problem. I set my newt up Alt-Az style with unlocked clamps to get the feel for how a dob might feel but didn't really get on with it. A 6" or 8" newt would be bigger than my 4.5" (if I'm struggling with motivation to set that up - a bigger one is a bigger problem). SCTs are outside my budget but I'm looking at a small Mak (OK for planetary but not good for DSOs - how often are the planets favourable?). A refractor appeals but I'd be limited in aperture by cost. What I have enjoyed is making more use of the newt I have, learning to align the mount reasonably well, learning what works and what doesn't and where its limitations leave me wanting. I've learn't that for light polluted skies an f/8 newt with spherical mirror is not necessarily a massive disadvantage (for me, at my current level and luck with the weather). I still want a smaller more portable set-up (and looking at a 4"-5" Mak on a GOTO AZ) for when I can get to darker skies without filling the car with gear, but I'm enjoying the learning experience with my old scope far more than I expected. I'm sure it's been discussed many times here, but keeping a diary has helped me enormously. I hope this helps - being a newbie to Astronomy (& SGL) I'm conscious this might seem too opinionated for one so inexperienced, if you feel this is the case please ignore it and excuse my ignorance - it has been posted with the best of intentions to try and explain (partly to myself) what is working for me and how things have improved. Regards, John.
  3. Thanks Guys, The link is really helpful - I'm using Pentax lenses (the Tamron has a swappable 'Adaptall-2' mount - perhaps allowing slightly longer lens register). The Kenko 'Lens2Scope' is the one I have for Pentax - nice robust piece of kit but lacks the ability to change the EP or use filters etc. I can 'Barlow' the lens by adding a 1.4x or 2x photo tele-converter between the two. So given I have a lens register of about 45mm, in order to keep infinity focus, I believe I need the EP lens at (or closer) than that (i.e. this has to include the distance through the diagonal) - does this sound right? Thanks for the suggestion RE the 20.5mm step-up - I'll have a think about that. John.
  4. Thanks Racey. The AllView was of interest in case I wanted to put my 900mm Tasco on it by flipping the arm. I like the idea of the Star Discovery FreedomFind but it adds £100+ to the combined cost of the mount & 127 Mak (compared to the basic SynScan outfit which now seems a better option).
  5. Thanks Geoff, those are really helpful. My Tasco is longer (about 100cm) & wider so it would max out earlier. I hadn't fully appreciated where the SkyMax eyepiece would end up with the scope vertical. John.
  6. Hi All, as per the title - is the 1.25" EP filter thread 30.5mm? The reason I'm asking is I have a photo Tamron 500mm f/8 mirror lens (a something-Cassegrain derived design) and a 10mm 45 deg angled prism EP adapter (the EP is built-into the adapter and can't be swapped). The lens has a rear filter thread (inside the mount) of 30.5mm (I don't know the thread pitch) and comes with a selection of filters (red, green, blue for monochrome film, and a Neutral Density) - I understand a filter must be used to maintain the optical path correctly - there's a Skylight filter in there at the moment. On the assumption the manufacturer would have picked a commercially available thread size - I presume it must be pretty close. It would be good to experiment with Astro EP filters in the lens but access is rather fiddly and I don't want to risk cross-threading anything unless I'm convinced it will work. There is a photo filter thread on the front, but at 82mm, good filters are very expensive. As the lens has no photo aperture control, the moon is very bright and being able to use a variety of lunar filters would help. I have considered trying to attach an astro 1.25" EP holder & star diagonal to the lens mount, but the very short register of about 45mm suggests there isn't enough room for infinity focus. Any suggestions gratefully received. John.
  7. Thanks Racey. I now understand that the Multi-function mount is another mount which also has FreedomFind, lots of photo features and the ability to turn the arm round for more clearance for longer scopes - something I'm going to consider.
  8. @Geof Lister - How long is your Tasco scope and do you have any problems with it hitting the mount? I ask because I've noticed that the AllView Multi-purpose mount allows you to turn the arm round to get better clearance for longer scopes. John.
  9. Hi All, after seeing Jupiter a week or so ago, I decided to fire up my old Tasco 4.5" Newt (f=900 on a wooden tripod & EQ2) - the previous time I used it I thought there was a problem with the mount but it must have been me driving it badly. I'm finding my feet again, having a few problems but enjoying it enormously. I'm managing to get a semblance of polar alignment (at least I can get Polaris in the FOV) and managed to re-align my finder on Jupiter tonight. I've started an observation diary (currently reading as Jupiter, Jupiter, Jupiter etc...) - which will hopefully help keep me motivated. No doubt I'll have loads of questions - I'm considering a new scope & mount, please be patient if I ask questions you've answered a hundred times before. I'm based in Lancashire, not far from Much Hoole (rumoured to be the place where Jeremiah Horrocks observed the transit of Venus). Regards, John.
  10. Hi All, I've tried searching for a similar topic but failed to find one - please point me to one if there is one: Having pretty much decided on a SW 127 Mak on an AZ SynScan mount (see general help 'Infrequent Observer...'), I've come across the SW Star Discovery - the FreedomFind feature looks quite interesting. Not being familiar with these mounts, I'm trying to work out what the differences are - so far I understand you can manually slew the Star Discovery and maintain alignment and can do this without power. Does SynScan offer anything not available on Star Discovery? I have downloaded the SynScan manual but can't seem to find one for Star Discovery, although there are references to the 'multi-function mount' - is this Star Discovery? Whilst the Star Discovery mount is only slightly more expensive than SynScan - it seems that I'd have to buy the Mak 127 OTA separately at a significantly higher combined cost - the only tube option seems to be the 150P which is much bigger than I'd planned - Have I got this right? Thanks, John.
  11. Um, OK there I was pretty much decided on the SynScan and I spot the Star Discovery mount: link - the next problem is by the time I've sorted tube rings and a dovetail, I'm not far away price wise from the Star Discovery 150P: link - this is much larger than I had planned but very inviting! The extra expense for the Star Discovery mount seems worth it - has anybody used the FreedomFind feature?
  12. It's usually an eyepiece accessory with a lens that increases magnification - they come in various multipliers: 2x, 3x etc. Since reading a few posts, it sounds like your scope may have one built in. My 114mm f=900mm tube is about 100cm long - if yours is about half that, then it's likely it has a 2x Barlow built in.
  13. Thanks Geoff - very useful. I'd probably try to re-use my existing tube collar by bolting it onto something resembling a dovetail. The hole centres are about 2.5" apart, with probably 6-8mm bolts so it shouldn't be too difficult... I think I've found an EQ2 to dovetail adapter should I want to put a newer scope on the EQ2: Link - based on this old thread it looks like the right one: Link although hard to justify due to the cost.
  14. Hi Shyam, I'm not enormously experienced but I have an old Tasco scope similar to your 114mm, f=900mm with (I believe) a spherical mirror. It came with cheap 1" eyepieces - SR4mm & H20mm. I have replaced these with a set of Mead MA 1.25" (Kellner I think) EPs (6, 12, 17, 20 & 25mm). The 12mm (75x mag in my case) gives me the best views of Jupiter followed by the 17mm, the 6mm give a larger disc but with much less detail & clarity. I have plans to try a 9mm and get a Barlow at some stage. Hope this helps, John.
  15. These guys have some success with airliners at altitude (scroll to the bottom of the page to see the optics they're using): Link I have an old pair of (cringe) Sunagor Mega-zoom 15-80x70 binoculars - they seem to have morfed into 30-160x70 in Argos these days!!! At 15x times they're good (not stellar), on a heavy photo tripod they're still usable up to about 40x if you're patient (I can see glimpse the bands of Jupiter) - once they've settled down and before it moves out of view, beyond that they're rubbish. It was seeing the bands of Jupiter and the 'squished ellipse' of Saturn that prompted me to buy my first scope. Ideally I'd like something like 15x70 or 20x80 with angled eyepieces - as they're not available I stick with 10x50 porro prisms (I might prefer 8x56 but can't justify it already having the 10x50s).