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I’ve spoilt myself twice today. First up, an XW 7 to fill a hole plus a basic camera bag for my EP’s, which I must say, for the money is perfect. Thanks to @faulksyfor the ‘inspired’ idea. 😀

30 minutes ago, HollyHound said:

Super fast delivery from @FLO again... only ordered this late Wednesday evening 👍

Unfortunately, I’m in meetings for the next few hours, so won’t get a chance to open it fully until then... so this is just a teaser 🤔

 

Your postie/DHL/Hermes driver Gary must be the fittest in the country 😆

Thanks for the ‘heads up’ just added the series just in case.

17 minutes ago, jetstream said:

When needed... sometimes 4-5 times a year but now they are in a sea can they stay much cleaner, longer.  My preferred method is a soapy water spray to rinse, followed by another soapy water spray, spray the fingers and very gently use the fingers to clean the mirror. Soap is a must as it lubricates. The final rinse is with distilled or "Aquafina".

This is just me, others will have different suggestions.

Slightly different method than almost everything I've read to date. How do you mean, "in a sea"?

3 hours ago, jetstream said:

Yes.

Contrary to some members beliefs I believe that a clean mirror is a must. A dirty mirror not only reduces DSO "contrast" through the eyepiece it adds scatter on bright objects reducing the quality of the view IMHO.

Some schools of thought maintain a dirty mirror is fine and brag about how long ago it was cleaned... I do not subscribe to this thought.

Begs the question Gerry, how often do you clean yours?

33 minutes ago, HollyHound said:

I don’t have that focal length, but the ones I have are superb in the dob, so I’m sure you may love this 👍

Im giving the 2mm exit pupil fl a thorough inspection to see whether I can lose the 13mm. If we bond, I’ll probably look at the 17. Need to add an XW 7 at the end of the month so I then have a slightly more balanced higher range.

The first rejig of my EP collection turned up today. 

I probably ruined my 5 year olds interest last year having shown her Jupiter and Saturn, I should have started with the moon and worked to that. She does seem to have a little fascination with the moon, which we have done more of with the binoculars.

Our eldest (17) did spare me an hour last December whilst I waxed lyrical about Orion whilst she viewed the trapezium. However, their mother has absolutely zero interest in any of it and won’t indulge me, never mind. I may have mentioned that it’s my escapism from her some of the time. 😆

12 minutes ago, Piero said:

 

My mirror is 1.5" thick. I start the fan at the highest speed when the telescope is still inside. So, I "wheel" it out, then go back inside to get better clothes, then go back outside with eyepiece case, collimate the telescope, and start observing. At this point I reduce the speed of the fan by half - the views are already acceptable (that's about 1/2 h fan on). Within another half an hour I might switch it off or just leave it at low speed, depending on how the night temperature goes.

 

 

 

P.S.

grip material on wheelbarrow handles is now yellow (black looks cool, but invisible at night time). Wood blocks for making that step ramp were a very temporary solution. I now use the following:

 

Next step is to make a good adjustable chair to be used with both the refractor and the dobson.

Love that!! I need to knock some ramps up too. I’m thinking of getting a little truck so that I can do it all in one go instead of breaking down the base and OTA, but certainly need to negotiate the door step. Hopefully save my back which I occasionally suffer with.

Nice report and sounds another great night out. It’s been persistently heavy cloud here now for 2 weeks so I think the final period before darkness ends Monday is a non-starter. Nice to be able to discount another purchase 🙂

44 minutes ago, Piero said:

My 16" F4, but also my 12" F6, regularly show far more details than my 4" Tak DF.

The refractor "wins" on wide field (3" Deg Vs 1 Deg fov) and solar observing (only possible with the refractor). 

 

Side note..

comparing top notch refractors like Tak, TEC, TV against low-end commercial dobsons is unfair. The optical quality is a major component, but there are other critical aspects in a newtonian telescope which must be considered to make it really fly.. at least the following: collimation (process+telescope mechanics for retaining it), mirror cell supports (back+side), mirror cooling, focuser quality, baffling, thermal currents, and (drum sound..) boundary layer above the primary. 

Whilst working on most of the list above reduces imperfections to a level in which these can be invisible to the eye, the last one can play like a "turbo" for magnification. After testing this, I really agree with the statement that a lot of the reported atmospheric seeing issues are actually 1-2" above the primary mirror surface.

As an example, the mirror box of my 16" is 11" deep and open at the back (Kriege design). Observing the moon, ~300x seemed the highest I could go before the image started softening. After pulling up the light shroud for 5-6" (this is enough to move the boundary layer away, as the mirror box is shallow) from the mirror box and defocusing the image intentionally, I could see substantial air turbulence going towards one direction (the warm air was blown away and moved up). Note that, this air flow only affects the air above the mirror surface, not the mirror side wall! An air flow directed at the mirror wall can impair the temperature across the mirror causing astigmatism and spherical aberration (tested on the other dob). After refocusing back, the image was getting better and better as the air flow stabilised.. the limit of 300x was pushed forward to about 650x (crisp). The images was still acceptable at around 800x (yeah.. viewing craters and details like from an Apollo spacecraft). What about stars? Thin diffraction cross on the bright stars, otherwise stars were pin points. Globulars? M13 or M3 at 300x were bright, with pin point stars all over and kind of star dust (not a diffuse cloud) near the core.

 

 

 

The element that I’ve not had issues with my 10” is cooling, but I’ve never really rushed it. Half an hour seems to be ample for mine. I did consider knocking together a fan, more for the hell of it, but I haven’t really felt the need for one. The point regarding the dob is that with cooling, collimation and the bulk to move, it is a longer drawn out process than a small grab and go frac. I’ve resisted the temptation of a frac just now, but the simple form for those opportunist nights will inevitably mean I’ll add one at some point. But, the views from the dob can be spectacular, M13 in my bortle 5 garden was beyond what I could have hoped for last year.

1 hour ago, faulksy said:

only 3 rolls of flock from flo. but better than nothing 😃

Flocking the Bresser? Be interested if you find an improvement m.

2 minutes ago, Deadlake said:

The other option, a lot cheaper elsewhere is this:

https://www.vanguardworld.co.uk/products/supreme-46d

I like the way the divider comes out, and is then a soft bag. Interesting design.

The puck foam can disintegrate with time and is not space efficent.

The problem is whether your collection is likely to change much. The bag works on that score but probably not best if you want a massive collection in one place. Bought a little nanuk case but have outgrown it a bit too quickly. Maybe one day I could see a small bino set in it..

27 minutes ago, Deadlake said:

I was plotting to get one of these cases:

http://www.max-case.co.uk/store/p16/max505cam.html

I currently have one of these

https://televue.com/engine/TV3b_page.asp?id=64&Tab=_epbag

but now I've got some large APM XWA's (17 cm long) they are to big for the bag even if I demote some EP's, the other option is one of these:

https://televue.com/engine/TV3b_page.asp?id=64&Tab=_ethos

 

I’m going to go with a camera bag this time like @faulksyposted, having similar EP’s. But, I’m probably going to keep mine to a set of 6. The Max case seems to be the best value for money option. 

2 hours ago, Littleguy80 said:

I think I’m finally done with my lockdown eyepiece case revisions. I’ve replaced the ES82 30mm with an APM UFF 30mm. The Lumicon UHC has been replaced with a new TeleVue Nebustar UHC, which arrived from FLO today. If APM ever produce something like the 30mm UFF in 40mm then that will be on my wish list. Other than that, I think I’m set…. for now 😁

Mine might look a little like a similar copy when it's rehashed shortly. The TV Nebustar is on my shopping list too this year 😀

There doesn't appear to be a break in this heavy cloud at the moment, again this week. Really want to see the difference. 🙁

1 hour ago, Deadlake said:

Which one, APM has a sale, €332 + vat for 10 mm

https://www.apm-telescopes.de/en/optical-accessories/eyepieces/58-74-wide-angle/other/nikon-nav-sw-10mm-eyepiece

Looking around has the Nikon SW been discontinued ?

It’s this version, though they don’t seem to have the 12.5mm in stock. They’re well out of my budget.

http://apm-telescopes-englisch.shopgate.com/item/32373639

1 hour ago, Littleguy80 said:

It's been a big improvement for me and has had lead to a definite drop in my use of the 10mm Delos. Although as I said earlier, the 10mm Delos offers advantages on fainter targets with the increased mag. For example, Saturday night I was looking for C/2020 R4 ATLAS. I couldn't see it with the Noblex though the nearby galaxy NGC 4314 was showing well. I initially mistook the galaxy for the comet. Moving to the 10mm Delos, I was getting a hint of the comet but not total confidence. I then switched to the Noblex with the Baader VIP barlow which I have set to give an approximate equivalent of a 7mm eyepiece. The comet became clearer at this magnification and I had the confidence to log an observation. Each step brought improvements.

I'll have to debate whether 100 deg is necessary at 10mm too. At 8mm I'll admit that it was nice to have, but at that mag, you are starting to drill into a target and so not totally necessary. But where's the line? 

I think that ultimately, if the 10mm is to replace the 13mm, then I'd need it. You have it nicely balanced with the 12.5 for ultra FOV and then drilling down from 10mm. 

13 minutes ago, Littleguy80 said:

Good plan. My original plan had been to keep the APM 13mm with the Delos 10mm and then get an XW 7mm. That only changed when I got the chance to get the Noblex. 

£1100??? I didn’t realise it was as much as that.

The Noblex is that good then. Sometimes I feel that the APM 13 needs a bit more contrast for sure, normally seems to be that the sky is still too bright. I haven't anything else to reference that against, it could just be the exit pupil rather than the contrast? The jump down to the 8mm has been too much normally there, so really am wondering whether 10mm is the remedy. 

13 hours ago, Littleguy80 said:

Mmmm that’s a tricky one. The first two 100 degree eyepieces I got was the 20mm and 9mm. For awhile, I wondered if I needed the 13mm at all. In the end, I got the 13mm as there were occasions when it was useful. At the moment, despite the 12.5mm and 10mm being too close on paper, I find what have works well for me. 

Maybe the answer is the Nikon Nav HW 12.5mm. I think that comes with a focal extender so you can use it as a 10mm too. They’re supposed to be tier performers. Pricey but if it’s two eyepieces in one….

Wow, I knew the Nikon was expensive but not £1100 expensive! I'm not in a rush at this time of year. Think I'll get the XW 7 and see if I can pick up a 10E secondhand, I shouldn't be out of pocket that way. Use that alongside the APM 13 and see how I get on. Whether 20 to 10mm is too large a jump, most of the time, I guess I need to work out. 

On 07/05/2021 at 22:20, John said:

I used to have a 40mm Aero ED - very nice eyepiece. I just didn't find it effective for me though because the background sky was just too bright with it. The 31mm Nagler is better in this respect but even that suffers a little so the 21mm Ethos and more recently the 17mm ES / 92 and the 13mm Ethos are my most used DSO eyepieces with my F/5.3 12 inch dob.

The 31mm Nagler works better with my F/6.5 102mm refractor where the exit pupil is under 5mm.

Well that's what I've found anyway

YMMV as they say  

Just reading through again and assuming your 12” is 1600mm, the comparable to your 21/13/8 core is 17/10/7 for me John. 

13 minutes ago, Littleguy80 said:

Mmmm that’s a tricky one. The first two 100 degree eyepieces I got was the 20mm and 9mm. For awhile, I wondered if I needed the 13mm at all. In the end, I got the 13mm as there were occasions when it was useful. At the moment, despite the 12.5mm and 10mm being too close on paper, I find what have works well for me. 

Maybe the answer is the Nikon Nav HW 12.5mm. I think that comes with a focal extender so you can use it as a 10mm too. They’re supposed to be tier performers. Pricey but if it’s two eyepieces in one….

I’m thinking now, that if I can pick up a 10mm Ethos, I’ll spend some time with it alongside the APM 13. I don’t want to ship the the 13, just in case. Maybe that could be the answer. At least if I pick one up at the right money, I won’t lose out too much either way.

1 minute ago, Xilman said:

I don't, as I said. I restrict myself to about x100.

I was commenting on figures presented earlier in the thread where figure > x250 were bandied around, as were sub-5mm focal lengths.

That said, back in the late 80's when I had a 18" Dob, a 10mm EP would give me over x200. Wasn't very useful so I stuck to (IIRC, it's been a long time) a 20mm, a 30mm and 2x Barlow for the odd occasions I thought high power would be useful. Only have a Skywatcher 250 now so the issue isn't as important.

Good point about an EQ platform. I'd like to find one which doesn't cost more than the scope. For me DIY means damage-it-yourself so making one isn't an option.

 

You do have a valid point. The 5mm at 254x was initially a little problematic, but notably the typical target have been planets and so providing the 9x50 was well centred, I haven’t suffered too much. Going over 300x sounds ‘interesting’ however..

1 hour ago, Stu said:

I think that’s just something with SkySafari. The rings represent the field of view accurately, but it does not show double star splits as they appear in the eyepiece. I’m not totally sure why this is, perhaps because it shows them larger than they appear in the eyepiece, so you have to zoom in more to see the split. So, don’t rely on it to indicate what level of mag is required to achieve a split, there are other calculations which are needed to do this.

Thanks Stu, I was hoping that was the case. Is there a rough calculation possible?

4 minutes ago, Littleguy80 said:

When I had all APM 100 degree eyepieces (200/13/9), I spent most of the time bypassing the 13 and going straight to the 9. Odd targets, like M33, seemed to like the 13mm. I also recall using the 13mm as a middle step when hunting down some comets. I now go 20 to 12.5 most the time and less frequently onto the 10. Part of the reason is the Noblex gives much better contrast than the APM 13. The extra mag of the Delos can help on some targets. I do go back on forth on whether the 10 is too close to the 12.5 but I think the Delos 8mm is too much of a jump. I also tend to start with the 10mm for Lunar/Planetary and work my way up from there. My instinct for you would be to go for a 10mm and see if you feel like you’re missing something in between. Another option is the APM 12.5mm 84 degree. It seems to have built a good reputation. 

My question to you Neil would be: if your 10mm Delos had the 100 degrees, would that negate the 13/12.5mm? I like the idea of 'less is more' in many ways. I'd rather spend that bit more on the core 3 that I use most. 100 degree fields have negated lots of EP's in-between I've felt.