lee g

5 minutes ago, Neil H said:

Hi I use this when I store my MAK 180 pro never had a problem of dew inside and the MAK is out in a cold shed

https://www.firstlightoptics.com/dew-prevention/astro-essentials-dual-fit-desiccant-cap-red.html

Thanks for your suggestion I actually ordered one yesterday 

57 minutes ago, Jules Tohpipi said:

If the tube is truly sealed then no that's not the reason. Same physical principles as why sealed double-glazing doesn't form dew/fog in the air gap [actually usually some inert gas but..] of the two panes when it's cold outside but warm inside. But does fog internally if the seal is broken.

If outside air can get into your OTA, then the act of heating your corrector plate would mean the heated air inside becomes capable of holding more moisture - and that extra moisture is supplied courtesy of the cold (but very humid) air entering from outside - on that particularly humid night. This hotter air then has to dump part of that extra moisture again when it drops below the dew point hitting your very cold primary mirror. 

 

When I say sealed tube I meant that in a loose sense. I mean air must have entered the tube whilst I attached the diagonal thus letting in some cold ambient air. So when I dried the corrector plate using the hair dryer I may have also heated the air behind it inside the tube which in turn caused the primary mirror to dew over 

So after reading all these helpful replies I think I’ve figured out what went wrong.

just before the primary mirror fogged up I had used a hairdryer to clear the corrector plate and I probably inadvertently warmed the inside of the tube up thus resulting in warmer air inside. Does this sound feasible in your opinions.

So my sct lives outside in a well ventilated shed. Last night I set up 2 hours before sunset when I went out to observe i turned on my dew strip heater on the secondary mirror, but within half an hour for the first time ever the primary mirror had fogged over. This ended the session there and then. How is this possible since the mirror sits in a sealed tube and how can I prevent it in the future.

2 hours ago, Louis D said:

What about getting a 20mm 100 degree eyepiece instead of the ES 24mm 82 degree?  It should have similar TFOV and eye relief but at a slightly higher magnification.  The various Lunt/APM HW rebrandings here in the US tend to be cheaper than the similar focal length ES 82 degree offerings.

Noooo just as I thought I had it all figured out 😂

After careful consideration I think I’ll be saving my pennies for now until a reasonably priced used ES24mm 82 degree becomes available after reading the replies to this post I don’t feel that an ES24mm 68 degree could bring enough to the table to justify its price 

nevertheless it’s been interesting reading and goes to show it’s never as straightforward as first thought 

7 hours ago, John said:

I'm still glad to have the 82 / 31mm for when I want to go as wide as possible though

I totally agree even though my 30mm is the least used I wouldn’t be without it.

4 minutes ago, inedible_hulk said:

Sorry to go off topic, but do you get much use out of the 30mm? It’s the only 82 I don’t own, but I have been put off by its size and perceived (to me) usefulness. I do like these eyepieces and I’m surprised they’re not more popular.

It really is a treat to look through though it is probably the least used mostly because of it size.

when I first bought the ES 82s I purchased the 30mm, 18mm, 11mm and 8.8mm as well as a 1.25” Barlow.

14 minutes ago, inedible_hulk said:

Admittedly it depends to some degree on your scope, but I doubt there’s enough difference to make it worthwhile. This is the field of view in mine:

red: 24 82 - Yellow: 24 68 - Green: 18 82

Wow when you put it like that it hardly seems worth it .

 Scopes I would use it with would be an 8”sct and a 120mm f5 refractor 

The 30mm 82 degree is a bit heavy for the f5 refractor 

I already own Explore Scientific 30mm and 18mm 82 degrees and always fancied filling the gap with a 24mm 82 degree but due to the high price I am now considering a 24mm 68 degree ep.

Do you all feel this is a worthwhile purchase or should I make do? 
 

I use my iPad Air with an asi air as it allows me to stack images using the asi app

Thanks for all your replies it seems then that ventilation is the way to go at least to begin with as it’s not an observatory as such. More of an external storage room for the scopes which doubles as a room to do EAA, keeping warm isn’t really an issue for me so maybe I can do without insulating it maybe I’ll just line it with plywood put some vents in and hopefully this will stop mildew/fungus growing on the optics.

I have a 5ft x 8ft wooden shed on concrete which I use to store my scopes. I also sit inside to do eaa and so it doubles as an observatory as well. Though when doing so the scopes sit outside.

Last winter it got terribly damp inside resulting in mildew. What would your suggestions be to stop this whilst also protecting the scopes from the elements?

I was thinking either ventilation and/or a dehumidifier but was unsure what to line the walls and roof with ie ply wood or some kind of insulation.

I was also thinking of interlocking rubber tiles for the floor.

I’m about to try my hand at EAA i currently use a cpc800 which is alt-az I’ll be using it with a ZWO ASI224MC USB 3.0 CMOS Colour Camera, an Asiair plus and an f6.3 focal reducer. 
considering the alt-az setup what kind of results can I expect using live stacking.

Yes this whole issue doesn’t seem very clear to me. As bosun21 states “If it’s meaningless” ie because the Asiair + does all the processing then why state it.

my worry is that the tablet would require more RAM when using the live stacking feature therefore having to constantly update the image as well as possibly running another app such as SkySafari pro. 
it would be helpful to hear from users who have experience in using their Asiair + for eaa ie live stacking.

My wife has bought me an ASIAIR plus for Xmas this will be powering a ZWO ASI224MC camera on my CPC800. this will be used mainly for eaa so obviously live stacking. My issue is my current iPad mini 4 has only got 3GB RAM and not the required 4GB do you think this would have a noticeable affect on the performance of this setup? I’m mostly worried about live stacking.

Finally after a lot of thought and waiting I’ve joined the club..

I want this mostly for EAA (live stacking) and maybe some planetary imaging.

only thing is I have to wait for crimbo now as it’s a prezzie from my wife 

I have to agree with the previous posts about it not being very good. Although I think maybe my discontent is due to my expectations that it should still in some way resemble the show I grew up with. Still I really do struggle with it.

maybe ditch the professionals and bring in a number of passionate amateurs to present it and keep the pros for guest appearances 

50 minutes ago, fifeskies said:

Is that a 1.25 wedge on the ST120.

Looks like it has used up most of the in-focus so I doubt that the longer path needed by the 2inch Coolceramic will allow it to obtain focus in an ST120 , unless anyone knows for sure that it does.

Nice little solar setup all the same

Just a note , I would remove the Telrad when looking at the sun , you can melt the target screen if the sun is high and strong and you accidently pass the strong sun across the top when aligning the mount , the little lens inside it can focus back into the Telrad

Point taken about the telrad I didn’t even think of that to be honest.. thanks 🙏 

I use my Herschel wedge with my skywatcher st120 and this gives great views.

all in all a very affordable solar setup 

I recently tried my hand for the first time live stacking at the eyepiece using a ZWO ASI224 Color Camera in my 8” sct after a few hours tinkering I eventually got what I considered acceptable results my question is do I now use any filters ie as you would for visual like uhc o111 ect, at the moment I’ve just been leaving in the ir cut filter.

These are my results so far they have however been slightly enhanced on my iPhone. I felt they met my expectations but please feel free to point out any flaws.

just to add I’m observing under bortle 5 skies

im trying to keep it as close to live viewing as I possibly can so the live view is more important than these slightly edited images.

On 18/05/2021 at 21:57, Louis D said:

Yes, it has a built in ND3 which is only good for photography by itself.  It also comes with a variable polarizing filter to screw into the bottom of your eyepiece to drop the brightness down enough for visual observing.  I set it to near it darkest point and then fine tune the brightness by rotating the eyepiece in the holder since the wedge slightly polarizes the light itself, allowing for more extinction at the first of the two stacked polarizers.  I've ordered a SVBONY ND3 (ND1000 in their parlance) to see if I like it better than the variable polarizer.

The image is certainly sharper and contrastier than when using Baader Solar Film.

The construction is very similar to the Altair Astro Herschel wedge, just in a 1.25" format and without the built-in polarizing filter.  I checked the rear ceramic, and it never got even remotely hot with my 90mm refractor after 20 minutes of observing.

Uniquely, it comes with a built in variable iris with many blades.  I tried it out for fun, but couldn't really see any point to it.  Why mask off aperture?  That limits resolution.

Is it safe?  Seemingly so.  Worst case, the prism shatters and all the light goes out the back instead of just ~92%.

Size wise, it's about the same as the 1.25" Lunt wedge.  It's a surprisingly heavy chunk of equipment.

Hi do you use a solar continuum filter with the Hercules wedge.

3 minutes ago, Stu said:

That’s just what I tried to answer for you Lee. There is no need to use the 2” eyepieces as the sun will just appear to small in them. Anything from 17mm and shorter will likely be 1.25”, and from my previous post, something anywhere  from 15mm down towards 10mm will give nice full disk views, even lower with 82 degree eyepieces.  I repeat though that complex eyepiece design are not always best for solar viewing, simple plossls can often give better results.

So, I would personally save some cash and buy the 1.25” Continuum filter.

That’s what I was hoping you would suggest mainly due to the price difference between the 1.25 and 2” filters.

 Thanks for sharing your knowledge 

15 minutes ago, Stu said:

Which eyepieces do you have? Solar observing tends to benefit from simple eyepiece designs like orthos or plossls. With only 600 mm focal length, there is no need for 2” eyepieces, a 11mm Plossl say will give around 1 degree of sky and x54. That will fit the full disk in (sun is about 0.5 degrees across) and give nice lowish power views. You could even go to a 15mm I guess which would give x40 and 1.25 degrees, depends what you are looking for. So, a 1.25” filter should be fine.

I have a diagonal which is either 1.25” or 2” and my ep’s are the explore scientific 82°some are 2” some are 1.25 so I was wondering which size solar continuum filter I would need 

23 hours ago, Barry Fitz-Gerald said:

I use a Startravel 120 with a Baader Solar Film filter (DIY) and a Baader Solar Continuum Filter, the views are very good, faculae, sunspots and granulation all sharply defined with good contrast. I have not used high powers preferring to see the complete disc in one FOV. 

So I’ve ordered a skywatcher st 120 and plan to get a solar film filter as well as a solar continuum filter. Would it be better to use 1.25 or 2” ep so I know what size filter to get.