badhex

I seem to have developed reverse aperture fever. On a recent holiday which was not specifically astro focused but included some dark skies, I took my ZS73 travel kit which is a lovely compact setup and weighs about 12 kg total, and fits in one cabin friendly backpack. I had about 4 sessions out of a toral of 23 days, and realised that there was a use case for an even smaller, lighter setup for these situations. Thus, I got this Evoguide and have a Baader T2 on the way to build the tiniest of travel kits!

My collection is a bit bigger than I thought! A-team Baader Morpheus 4.5mm Baader Classic Ortho 6mm Baader Classic Ortho 10mm Pentax XW 10mm Baader Morpheus 17.5mm APM UFF 24mm Aero ED 2" 35mm Aero ED 2" 40mm TeleVue Panoptic 2" 41mm APM Superzoom 7.7-15.4mm B-team BST Starguider 3.2mm BST Starguider 5mm BST Starguider 8mm Meade 5000 HD-60 9mm BST Starguider 18mm Meade 5000 UWA 18mm Maxvision SWA 24mm Celestron Plossl 25mm Skywatcher 2" LER 28mm GSO 2" Super Plossl 30mm Seben Zoom 8-24mm 0.965 team Swift 0.965" Kellner 12mm Celestron 0.965" Kellner 18mm Swift 0.965" Kellner 20mm CZJ 0.965" Huygens 25mm Swift 0.965" Kellner 26mm Charles Frank UW So, that's 27 not counting 2 Powermates, 2 GSO barlows, a 0.965 Barlow and a load of random other cheapo stuff that came with scopes.

Also, your ruler test posts provide a great immediate image reference of views for people when contemplating a new EP. I have certainly been convinced a couple of times due to those!

Excellent news! Thanks again for all your hard work here @Ags, I will be ordering this soon!

Ah, sorry for clarity I meant that an overly large exit pupil results in wasted light if your own pupil cannot dilate that much. I'm don't know for certain what my pupil dilates to but as I'm approaching 40 I suspect it's less than 7mm. Regarding mention of edge performance, I meant more the eyepiece edge performance than your own eye specifically.

Hi @grjsk a couple of Qs: What scope are you using it in? Is the scope sufficiently cooled prior to use? Are the aberrations/artefacts over the whole field of view or just around the edge? What effect does defocusing have (both intra- or extra- focus)? Have a look at this page for the various diagrams which show different types of aberrations to see if any of these match what you're seeing: https://www.handprint.com/ASTRO/ae4.html

The Starizona does indeed slide into the focuser body of the Evoguide, and looks like it has both a female T2 to screw on to the focuser, then a male T2 for the camera (or diagonal in our case). The clear aperture of the FF is 28mm apparently, so should be good for all 1.25" EPs I think?

I just checked the spec and the Skywatcher FF has a backfocus distance of 17.5mm, so I don't think it would be possible to connect the diagonal as well. Starizona apparently do a field flattener with 55 mm backfocus however, and it's T-threaded so I reckon you could pop a Baader T2 prism on there at a push (I intend to do this although not with the FF). I'm not an image train expert so not sure if my assumptions are correct.

Thanks! Yes, same issue with my finder, stars almost look like clusters or nebulae when at the edge. I wonder if the field flattener would help here for visual? Looking forward to your first light report. What's the CA like in the daytime? Hoping it would be a lot better than my finder given that the Evoguide has FPL53.

Hello Magnus, I was wondering how you got on with the first light? I'm planning to potentially build a tiny scope using the method @DRT used, i.e. T2 prism diagonal with a low profile EP holder. I was playing about with my TS-Optics 50mm RACI yesterday as a test to see if there's enough light gathering for my needs. It is nice as a finder but as a scope for actual observing, it suffers with off axis CA and field curvature, so I'm hoping that the Evoguide is better? Eager to hear your thoughts.

Nice. Those Ikea trolleys are surprisingly robust, although the wheels do leave something to be desired as you mentioned. In Berlin there is a lot of second hand/given away trade in furniture so it's quite normal to see people on the U-Bahn carrying an entire sideboard or giant shelving units, and we were no exception. We bought an Ikea trolley seven years ago when we moved here and it's still going strong; we have had all manner of ridiculous stuff on the back of it including the kitchen sink!

It's on Spotify and a bunch of other podcast services, nice podcast overall. I just had a quick listen to 163, the initial review of the Masuyama is from 25m40s in, but episode 168 also has a quick review of the 30mm UFF.

I think there's a episode of the Actual Astronomy podcast which discusses the 32mm Masuyama as well. Just looked it up, I think it's episodes 163 and 168.

Yes, the ED 40mm and Pan 41mm give exit pupils of 6.79mm and 6.96mm respectively in my ZS73 so I'm pretty sure I'm losing photons with both, although I have not measured my max pupil dilation. I'm close to 40 so I imagine it will not be 7mm!

No, certainly not in the ZS73 anyway - I should have a go with that. IIRC the Panoptic is sharp to the edge at the cost of angular magnification(?) , but it don't use it often so will have to confirm that. It's only recommended for F7 or slower by TeleVue I think? It's a shame APM don't make a 40/41mm version of the UFF for max field 2" usage, that could be a winner!

I have been thinking that I need to try out the 40mm and 35mm side by side in my ZS73. Have been using the 40mm and ZS73 quite a lot recently and in general I really enjoy it. It definitely suffers at the edge but I'm not sure which performs better in that scope. I also recently read that as well as obviously wasted light which I knew about, an overly large exit pupil can supposedly exacerbate some potential aberrations caused by your own eye? Trying to remember where I saw this. Last time I had an eye test a few years ago, the doctor said I had excellent vision with no issues, but maybe the larger exit pupil on the 40mm is causing some issues too?

Managed a few hours by the side of a road with my travel setup while recently on holiday in Ponza, Italy. The skies were excellent - MW easily visible naked eye along with a number of other targets. The side of the road was not ideal, however, a lot busier than first thought so I had to close my eyes every few minutes when the cars whizzed past.

Caught a nice shot of our nearest neighbour basking in the fading light from our star whilst recently on holiday in Ponza, Italy. Captured handheld on a Samsung Galaxy Note 20 Ultra. Minor editing in bundled phone apps.

This thread is dangerously good!

SGL for life 😂

I can confirm the Powermate works well with orthos - have used my BCOs my 2.5x a few times. As mentioned by others the larger EPs like Pentax and Morpheus are a bit unwieldy with a 2.5x Powermate, but I also got a 2x2" for this use case. It does add some weight but feels sturdier, and looks less silly. 2x is also useful as 2.5x is sometimes slightly more than I want. Conversely, an ortho in the 2x2" looks ridiculous!

Great collection! But why are the two cartons upside down?

I've just realised I misread, I was thinking the 115mm was a doublet. Although technically 'better' in terms of colour correction, as @bosun21 has said, the doublet is essentially CA free for visual, which I understand is your main use case and not AP. This leans even more into the 115mm not being very grab-and-go compatible, as the additional element will increase cooldown time quite a bit. Honestly I don't think you will be disappointed with the 102!

Hi Marian, Is the 102mm the Photoline model you're referring to? https://www.teleskop-express.de/shop/product_info.php/info/p9868_TS-Optics-Doublet-SD-Apo-102-mm-f-7---FPL53---Lanthan-Objective.html Assuming it is, I can strongly vouch for this telescope as I have the same one. It is also identical to the Starfield model which many of our UK based friends on SGL own. It's a fantastic scope! As far as I can tell, the 115mm is essentially identical but scaled up, which means a bit more light grasp, but I believe it's almost 2kg heavier as well which makes it less portable, so won't work as well for grab and go. The additional light grasp might not be worth the trade off. One other thing is that with a low power 40mm EP you'll be able to get about 4 degrees of sky in the 102mm vs about 3.5 degrees in the 115mm.

Seems like even fishing cannot escape those dreaded undercuts!