Louis D

On 03/06/2024 at 10:40, Louis D said:

I don't know about Europe, but many US airports in larger cities have issues with organized gangs fleecing travelers of valuables from checked bags.  Typically laptops, tablets, jewelry, cameras, etc. are stolen.  I'm not sure they'd recognize astro accessories as valuable on their checked bag X-ray scans.  They typically have someone in security who is woefully underpaid designate bags for "further inspection" where an accomplice then opens the bag for inspection and confiscates "suspicious" items, closes the bag without a note explaining what was "confiscated", and sends it on to its destination.  Investigative reporters have put hidden Air Tags on such items in checked luggage and tracked them to their ultimate destinations.  The police just treat it as lost luggage, and thus a civil matter.

Here's an article about how a passenger was able to get criminal charges brought against someone who stole her luggage, but only after tracking down their items, peeping in windows, and calling the sheriff.

The Pentax XW line is very good from 3.5mm to 10mm, and they're $30 cheaper than the Morpheus line, at least here in the US (Pentax = $269, Morpheus = $299).

This thread on CN about diffraction pattern simulations might be an interesting read for some.

I've literally compared the Svbony to the Lumicon UHC and both Lumicon OIII filters I have (1990s and mid-2010s), and the Svbony is only a slight step behind the Lumicon, and both are a big step behind the OIII filters.  Under Bortle 6-7 skies, the increase in contrast from the Svbony or Lumicon is dramatic.  I blink-swapped the two UHCs looking for improved contrast and nebula extent, and I could only detect a 5% to 10% change in either.  I was rather surprised.

I could not see a 10x improvement in either contrast or extent between the two UHC nebula filters.  Perhaps if I observed from Bortle 1-2 skies I would notice such a remarkable difference.

Here's the spectra for the line filters group:

Notice relative to the Lumicon UHC that the Svbony is tighter in the H-alpha region, passes only a bit more green where light pollution is most noticeable, and mostly passes more violet-blue which I don't find all that much affected by light pollution.

If budget is tight, I recommend the Svbony UHC.  It's wider in passband than the premium brands, but it really helps to cut light pollution and improve contrast.  In the US, at least, the 1.25" version is under $20+tax on Svbony's website.  Despite already having a very good Lumicon UHC, I bought one at that price a year or two back just to see if they're any good, and they are.

Welcome to SGL with a great big Howdy! from your neighbor to the SW in Texas.

I have an older Meade UV/IR cut filter on the front of my Hercules wedge, and I've never noticed it getting hot in my 90mm APO.  Since it reflects energy rather than absorbing it, that's not surprising.  Couple that with a KG3 substrate, and the residual IR being absorbed is probably minimal.  Certainly not enough to heat up.

2 hours ago, Oscar23 said:

I've often seen nebulas and globulars called "faint fuzzies", and they aren't wrong, they are very hard to see and even harder to see any detail in!

Try a UHC or OIII filter on some of the nebula to see if you can get better contrast relative to the background.

Boost your power up to around 200x to resolve large globulars like M13.  It isn't fuzzy in the least at that power.

I saw quite a few folks using ZWO AM5 mounts with their matching carbon fiber tripod at a recent star party.  No need to carry around counterweights as added dead weight.  I don't know about Europe, but they're on sale as a set for $1999+tax here in the US right now.

My finder arrangement with RACI, GLP, and QuikFinder:

My finder arrangement with RACI, SkEye, QuikFinder:

The 150 (at f/5 in the Heritage or an astrograph) is going to be much more compact.  The 250 is pushing the limit for me of luggability.  200 tends to be the sweet spot, so I would start there.

2 hours ago, duncanjameshill said:

would you be OK with packing your mount, eyepieces and diagonal in your checked luggage?

I don't know about Europe, but many US airports in larger cities have issues with organized gangs fleecing travelers of valuables from checked bags.  Typically laptops, tablets, jewelry, cameras, etc. are stolen.  I'm not sure they'd recognize astro accessories as valuable on their checked bag X-ray scans.  They typically have someone in security who is woefully underpaid designate bags for "further inspection" where an accomplice then opens the bag for inspection and confiscates "suspicious" items, closes the bag without a note explaining what was "confiscated", and sends it on to its destination.  Investigative reporters have put hidden Air Tags on such items in checked luggage and tracked them to their ultimate destinations.  The police just treat it as lost luggage, and thus a civil matter.

I've tried a bunch of filter combinations to reduce CA on my 152mm achromat and ST80.  The Baader Semi-APO helps a bit to remove the majority of the violet while not disturbing the color balance too much.  It does this by utilizing a 450 to 460 nm light yellow filter to block some violet on a Neodymium substrate that blocks the yellow-orange part of the visible spectrum to compensate for the excess yellow.

The best, cheap compromise I've found is a 470 nm long pass (yellow) filter that I picked up from a commercial filter supplier.  It is stronger than the typical astro Yellow #8 (~450 nm LP) and weaker than the Baader 495 LP.  A photographic Yellow #8 is roughly a 480 nm LP filter, and would be my second recommendation.  It's a bit too strong, but much less objectionable than the 495 LP or a Yellow #12 which is about a 510 nm LP.  They are available in 48mm sizes which fit 2" eyepieces or diagonals perfectly.

The more vexing problem is how to cut unfocused red at the other end of the spectrum once the unfocused violet is truncated.  This requires a cyan or short pass (SP) filter, which are only available from commercial filter suppliers.  I've found a 625 nm SP to be about the best compromise.  Thus, a 470 nm LP stacked with a 625 nm SP is about the best I've found for making fast achromats usable for high power work.

The only Chinese/Taiwanese made focuser I really like came with my KUO 152mm achromat.  It doesn't slip under heavy loads, it has a hefty feel to the focusing action, there's no sponginess or notchiness to fine focus wheel, etc.  I wish they sold it separately.  The only thing it needs redesigned is the focuser rotator which grinds, grabs, and feels loose until completely locked down tight.

The GSO focuser that came with my 6" f/5 Newt is borderline awful.  Set the tension too high, and it won't move.  Set too low, and the draw tube drops down by itself under load.  The fine focus is good on it, though.

The focuser that came with my Astro-Tech 72ED slips like crazy under any load above one pound.  The fine focus is good on it, however.

The focuser that came with my TS-Optics 90mm Triplet APO (likely Sharpstar made) has a spongy feel to the fine focuser, along with considerable backlash in its action.  It will also unwind under heavy load despite having a helical R&P.  It will literally spin the focuser wheels while doing this.  A properly designed helical R&P won't do this.  To combat this, I have to keep a certain amount of drag on the pinion tension screw which messes with fine focus.

15 hours ago, AstralFields said:

But I can clearly see the Coma in my 65 degree 14mm eyepiece.

Rack focus inside and outside of best focus on a fairly bright star.  If it defocuses to a radial line on one side and a tangential line on the other side, you're seeing astigmatism, not coma.  Coma should look the same on both sides.  There could be some coma present at best focus adding a radial, expanding gray tail pointing away from the center.  If at best focus you're seeing a rainbow tail pointing away from the center, you've got chromatic aberration.

12 hours ago, VNA said:

Hello, I see craters!

4 hours ago, Mandy D said:

Me, too.

Were you two the type who, when laying on your back in the summer looking up at puffy white clouds and were asked what you saw in the cloud shapes replied "Clouds". 😁

Reminds me of the Indian festival Holi:

I see a wide mouthed, crazed Pikachu:

That, or perhaps a cat that splattered onto a windshield. 😁

Obsession 18" Classics were going for about $4500 pre-Pandemic on CN Classifieds.  I can't find even one listed since 2021.  Figure maybe $5000 to $5500 today.

Obsession 18" UCs have been going for about $5000 to $6000 over the past two years.

Just saw this beautiful Matthias Wirth 16" Dob come up on CN classifieds for € 3650.  The scope is located in The Netherlands:

Looks to be quite lightweight and compact to store.

Planetary diffraction spikes really only bug me when they cover up a moon I'd like to observe.

OMG, sorry to the OP for having derailed this thread.

18 hours ago, TiffsAndAstro said:

I won't be buying a Ferrari until I can at least change gears in my fiesta a bit better first

The Ford Fiesta name is a blast from the past here.  They were discontinued in the US after the 2018 model year.  I never did see very many of them in Texas, despite the name sounding like it would have been a favorite among Hispanics, they tend to favor full sized pickup trucks to double as work vehicles.  The Ford Fusion was about as small as most Americans wanted to buy.  It has also long been discontinued in the US market.  Ford hasn't sold any sedans in the US since well before the Pandemic.

I would add that galaxies in general are hard to observe under light polluted conditions.  Even M31 and its satellites reveal only their cores under my backyard skies.

I would add M22 if the observer is far enough south as I am (~30° N) to easily observe it.  It is just as impressive and easy to locate as M13.

Otherwise, you've covered most of my go-to objects for public summer star parties. 👍

If you have light polluted skies, there's no real reason for an illuminated reticle.  The black lines of a non-illuminated reticle are super easy to see against the background skyglow.