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  1. Yesterday
  2. Nightspore

    Pentax XF Zoom

    The Pentax 31.7mm (1.25”) XF 6.5-19.5 Zoom eyepiece at 240 grams is about half the size and weight of its larger sibling the XL 8-24 Zoom. The apparent field of view ranges from 42° to 60° with a claimed eye relief of 15mm to 11mm. It has multi coated high-refraction, low dispersion lanthanum glass consisting of six lenses in four groups. The XF stands 90mm tall with a diameter at its largest point of 50mm. Like the XL it is also waterproof and has a twist-up rubber eyeguard. The larger Pentax XL zoom had performed superbly with my 102mm Altair Starwave ED doublet. So I was looking forward to testing the smaller Pentax with my Sky-Watcher Evostar ED80. Especially as it has a similar focal ratio to the Starwave but is on a lighter mount/tripod combination. The magnifications with the XF and the ED80 are comparably similar to the XL and the Starwave. Using the ED80 the lowest magnification is 30.7x for 1 arc degree, 22 minutes and 5 arc seconds of true field of view with a decent sized exit pupil of 2.6mm. The highest magnification is 92.3x for 39 arc minutes of TFOV with an exit pupil of 0.86mm. This range of about a two and a half to a one millimetre exit pupil is a nice sweep of what could be described as a medium magnification series. The XF effectively replaces several eyepieces. Ideally and potentially you could venture out with this zoom, a Barlow and a large rich field widefield eyepiece and have a complete magnification range for an entire night’s viewing. My original plan was to use the 31.7mm XF in combination with a 51mm Baader dielectric diagonal but ended up with placing it in the 31.7mm Baader (Zeiss prism) Amici as I’d been looking at the Moon earlier with another eyepiece and was just too lazy to change diagonals. Predictably the first light target with the XF was the lunar surface. At 30.7x the Moon was clear and bright although I inevitably zoomed up to 92.3x which is the highest I could go without using a Barlow. The detail in the Atlas and Hercules craters was stunningly sharp, as was Posidonius and in the general Lacus Bonitatus area. When my eyes had adjusted to the dark a bit after the lunar observing I split some doubles, including Gamma 1 and 2 Andromedae (Almach). The bright Moon wasn’t helping much and I was also losing the transparency. As I waited for M42 to rise high enough for a decent view I looked around a Cassiopeia that was close to the zenith. The Double Cluster and the Owl Cluster were pretty impressive considering the overbearing moonlight. I could detect no light scatter. Stars were sharp virtually to the edge and overall colour separation and contrast were superb. Although this is not too surprising with an f/7.5 scope. The XF field stop seems slightly smaller and more restrictive than the XL stop, however I got the feeling that this was a bigger eyepiece than it actually is. The 42° of field on the lowest magnification tends to feel a little restricted. The only real remedy for this is increasing the magnification slightly to open the field up more. Although this is more or less de rigueur with most zooms. Eventually the Orion Nebula had ascended just enough for me to get a relatively decent view. The Trapezium stars were very defined and the nebula could be seen faintly. Even with the obscuring and slightly hazy conditions I was impressed with the Pentax XF.
  3. Bottletopburly

    Mulling camera over

    Managed to track a 5v usb powered dummy battery on aliexpress had one on the canon so no worries running out of power https://m.aliexpress.com/item/32685085906.html?trace=wwwdetail2mobilesitedetail
  4. BAZ

    Roll on/off shed obsy build

    Looks very tidy Ron. You just need some clear skies now mate!
  5. Ron Clarke

    Roll on/off shed obsy build

    Well a bit more done, valancing around the top to secure the roof felt and an extra lock on the doors. Ready for painting now, same colours as the shed.
  6. Ron Clarke

    New Obsy

    New obsy build starting 04.10.2019
  7. Derbyshire Dave

    Sh2-114 ha - here be dragons

    Wow! Really good! You put some effort in there Steve!
  8. Bottletopburly

    Mulling camera over

    Checked camera last night shutter count is 1800 resolution is 6000 x 4000 pixels and pixel size is 3.92 .
  9. Last week
  10. Ibbo

    M31 Lum from home

    I very much doubt it . I think it could be the lens spacers diffracting the brighter stars.
  11. Graham

    M31 Lum from home

    Looking at the star/galaxy center right of 31. You dont think you might have found a supernova do you. There seems to be a bright light source just left of center of it at around 8 o'clock .
  12. Ibbo

    M31 Lum from home

    If I get the chance tonight I will throw all the data at it and see what comes out. Its a bit of a fiddle getting it this far.
  13. Graham

    M31 Lum from home

    Looks good to me.
  14. M31 from home after about 6 hours with the Tak collimator last weekend. Slighty better stars but still the odd shape on one or two of the brighter ones.
  15. tuckstar

    Hi from Newbie in Notts

    A nice selection you have there.
  16. AstroTim

    Hi from Newbie in Notts

    Thank you all for the warm welcome. In terms of kit, I have a C5, C8, Binoviewer, and a few eyepieces + a 2x Barlow. I have also recently acquired a ZWO colour camera but have yet to use it in anger (I’ve spent a couple of evenings taking some test captures but I’ve yet to work out how to get a decent image from it). I have been trying SharpCap, Autostakkert, and Registax to capture and process the images. The seeing wasn’t particularly great on the evenings I had a go at imaging though. Tim
  17. Allan the Plumber

    EMS5 free pitch

    Sorry 😐
  18. Derbyshire Dave

    EMS5 free pitch

    Thanks Bryan, very helpful
  19. Derbyshire Dave

    EMS5 free pitch

    Shame Allan, we'll miss you
  20. philjay

    focal reducer

    Its all down to reducing the focal length, the fr you mention will take it down to f6.3 yes, which is slower than a startravel. You can get faster focal reducers for sct,s but what you gain in speed you lose in flat field. These fast focal reducers are ok (ish) for small chip ccd cameras but poor for larger chip cameras. Trying to get fast, wider field images with an f10 sct isnt easy, Celestron and their Fastar compatible sct,s are the best way of doing this.
  21. Bino-viewer

    EMS5 free pitch

    Thats the route i'll be taking......and i'll have a navigator with me this time as well 🙂
  22. Ibbo

    EMS5 free pitch

    This one Some folks have been concerned about getting large RVs and caravans up to the site. The best route isn't the most obvious: If you're coming up the A396 from Tiverton and the M5, don't turn off for Dulverton or for Winsford, but continue on the A396 and take the B3224 heading for Simonsbath. When you get to Exford, note the White Horse pub just before the bridge over the Exe (decent bar meals). Continue toward Simonsbath about a mile and then turn left towards Dulverton. This takes you over Winsford Hill, heading Eastward to approach the campsite from above, along wide and not very windy roads. Hope that helps, Bryan Thats the route I followed on google maps
  23. Sheila

    EMS5 free pitch

    There is an earlier post that tells everyone with large vehicles which route to take
  24. Ibbo

    EMS5 free pitch

    Having spent a bit of time on google maps street view it is a case of like normal take a bit of care on the curvey and narrow bits.
  25. philjay

    Happy Birthday Craig.

    Happy birthday Craig
  26. Sheila

    EMS5 free pitch

    I have seen large caravans on the site so I am not sure how they got there then? I am certainly in trouble as I only have the bus to go there in if it’s too narrow
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