Deadlake

The Antlia performance drops below F3, maybe that is what is being seen? Antlia H-alpha Pro narrowband filter optimizes the FWHM (full width half maximum) to 3nm bandpass. As the bandwidth becomes narrower, the 3nm Pro narrowband filters enhance contrast of emission targets by lowering the unwanted background signal. Antlia H-alpha 3nm Pro filters are designed to deliver 88% transmission at the 656.3nm line which provides you with the maximum signal and well defined nebulae structures. Conventional broader narrowband filters cause a heavy loss in transmission due to the strong Center Wavelength (CWL)-shift. We guarantee T>88% within 1nm range of the center bandwidth, which means that the 3nm Pro narrowband filter can guarantee high transmittance for working with both long focal ratios and fast optical systems. Blue-shift data shows that Antlia 3nm Pro filters can be used with nearly all systems as fast as f/3 with minimal loss in emission signal and meets the requirements of fast optics like Hyperstar and RASA. The out of band blocking specification is rated OD5 (0.001%) which delivers an excellent SNR(signal to noise ratio) and effective cut-off rate to minimize interference from other wavelengths. Improved sharp cut-off astrophotography 3nm Pro filters are designed to minimize halos around bright stars. Application and Performance High transmittance and smallest bandwidth to maximize contrast Steep spectral profile minimizes halos around bright stars A single substrate to eliminate internal reflections Narrowband Objects: H-alpha Emission Nebulae, Planetary, Wolf Rayet Nebulae and Supernova Remnants Use in light polluted areas and dark sites Extends imaging time when the moon is up Antlia narrowband Pro filters can be used down to F/3 systems with slight loss of signal All Antlia Narrowband filters are edge blackened to eliminate internal reflections from stray light Superior optical reliability reduces post image processing This filter is not suited to deep sky objects that do not contain H-alpha emissions. Technical Specifications Basic Substrate: Schott optical substrate Filter Thickness: 2mm+/-0.05mm for 2'' mounted FWHM (Full width at half maximum): 3nm CWL (Central Wavelength): 656.3nmnm Peak Transmission: ＞88% Blocking: > 5 OD(0.001% out of band blocking) @ 300-1000nm Surface Quality: S/D (scratch/dig)= 60/40 (Refer to MIL-O-13830) Transmitted Wavefront: Lambda/4 or better. Parallelism: less than 30 arcsec Single / Non-glued substrate

@GavStar is not far, he has a Chroma. Maybe when the moon is not in control and the weather is good we can do a comparison. I don't know anyone on CN that has both filters to do a comparison. The only thing I have too go on is that I've never seen a Chroma 3 nm H-Alpha filter for sale in the second hand market I do see Antlia 3 nm Pro's advertised. I'd expect a brighter image with your scope one F stop advantage. The only difference is the shape of the stars etc, not the brightness of the image. I'm sure other people will comment.

I was looking at HH and Flame nebula last night: SQM 20.89 Transparency: Medium Scope: LZOS 130/F6 with TV 67 mm NVD: OVNI M 2100 FOM Filters: Baader 6.5 nm f2 and Antlia 3 nm Pro H-Alpha I swapped between both the Baader and Antlia. On previous nights I thought there was not much difference between the two filters, the transparency was better on that night. Last night Sunday 6 February the Antlia seemed a little better at pulling out contrast, however the difference between the two is not as much as I expected. I'm coming to the conclusion that the Chroma might be the way forward, however given the Chroma's cost I'd like to observe with one before buying.

This is true, how many AP refractors get reviewed against AP reflectors for example. Maybe a Mewlon versus a TOA would be good, but the marketing blurb always tells us of APO's like view from the Mewlon.

I’m coming to the conclusion that if I want to swap EP’s a weight on the Losmamdy bar is the best solution. The scenario is using a TV 55 mm and then swapping to a 20 mm XWA. The FT3545 will be totally out or nearly all the way in and that changes the balance. No other solution.

But how many scope models compared with Takahashi?

This is true, for scopes they have one model the AP130GTX. Now just a mounts company, a bit like Vixen in Japan.

I agree @johninderby, it takes as long as it takes too beta test software in the field. Also this is really Rowans first software project (I guess) and a bit of a reputitional risk for them. If it goes wrong then some telescopes could get broken. Of course maybe if Rowan shipped some beta mounts to the US where they have constant sun Rowan would get more consistent testing of the mount...

Surprised you have not got another one to bino it on your panther aka this user with a pair of TOA-130’s. 😃 Actually Japan seems to have an amazing collection of bino kits for converting two APO’s into bino scopes, whereas in the west BV’s are more popular. Just cost I would presume….

You where not tempted by a 6" BS scope then?

Looking at the performance report is this poly Strehl or at a particular wave length? Also PV of the lens has an effect. But now Far East is showing performance reports hard to ignore compared to top tier. Having said that I know some AP owners rate that brand high then the Takahashi's they also own......

Any difference when it comes to attaching a ASA reducer between the different TS models, e.g when going from F4 to F2.9? Is it as simple as inserting the ASA reducer or more complicated?

Quantum tunnelling is a mechanism via which Hawking radiation could operate, see: https://www.hindawi.com/journals/ahep/2014/168487/ and there are many hits. The precise mechanism is still hypothetical.

Black holes evaporate over time, via Hawking radiation where photons quantum tunnel thru the gravity barrier. However this occurs over lifetime of the universe timescales. The recent Universe series has a good discussions on this.

One question Mike. Given you have a NP101 @ F5.5 Why not add a barlow and just need one scope. Ignoring the fact you want to look side by side or like collecting them?

Ha Ha colour scoptic vision. 😃

To be honest any 6" and over refractor I would want to locate in an observatory. It's not just the weight of picking them up, it's on a cold winters night the opportunity to slip over and opps is very high. I usually take my 5" in wearing gloves otherwise my fingers would get frozen to the handle. My advice would be to go with a 5", if your budget is just for the scope then the AP130GTX is meant to be better than the TEC or Takahashi scopes around 5" for visual use. I've not looked thru either just based on first hand reports. Then other item to consider is the mount. Given the weight of the scope and you are not doing AP, I would consider looking at a harmonic mount. The reduction in weight makes setup easy and hence will increase your use of the scope. Given your budget as well, if your interests are "widefield with planetary nebulae and general deep sky" then maybe a high end APO is not the best option. An NVD would make your back garden a dark site, so on a moonless night you could view those objects. See: Same time the clarity of stars thru a wide field APO telescope really has to be seen to be understood. I quite using NVD paired with a APO as I can swap between the two and take it all in.

How effective are using BV's to observe Jupiter, would be interested to know? I suspect I might need to Barlow them to get enough magnification. Plan: 130 mm/F6 GPC 2.6 in MaxBright II 10 mm UFF Thanks

Which EP's where you using TOE 4 mm or HR 3.6 mm?

It's not a simple answer since it depends on a lot of factors around the viewing environment, aka sky brightness and transparency. For a 130 mm APO F6 or faster scope afocal usage, for speed reasons. EoF is a minor concern to get a high contrast image. Would post photos but phone holder in the post, views are similar to Gavins excellent shots from last week with his AP130GTX or FSQ-130. For a larger focal length than prime in a Newt as better EoF in my use case, however a C11 is tempting as the EP is in the correct position for mounting on an EQ. Which is why I suggested reaching out to some users in the US who can give some feedback as they have used both set up's. Also remember @GavStar NVD tube is vastly superior to my tube and in certain tests sets records on previous tests recorded by CN's NV community. This means a slower set up at longer focal lengths can be used, the C11EdgeHD will be subjectively running around F4.

I agree with @GavStar that in a Bortle 8/9 environment then speed is everything (within reason) and for a 130 mm scope APO F 5.5 / 6 scope afocal will deliver the fastest system and hence brightest image with most contrast. For context when @GavStar mentions a 130 mm I presume its is an AP130GTX 😃 Back to the C11 EdgeHD versus Newtonian, this really does split NVD users and there are quite a few different views in the US. The attraction for me was quite a small NVD stack as the NVD I use supports prime. At the same time the C11EdgeHD is quite compact, and if its on a EQ mount then really viewing through a Newt would not be the best ergonomics. I guess then question is what more would you get out of a C14 EdgeHD over the C11EdgeHD as far as NVD goes? If I want super sharp stars and planets I'll take my LZOS APO any time.

This is a main factor for a decision. I’d then bring in a fast Astrograph into the equation as the NVD needs to be illuminated with a flat field to avoid EoF effects. Looking at an SCT first, the SCT will need adaption with a AP 0.75 reducer, not any faster as you need back focus. You will then need the usual TV 41 panoptic and TV 55/67 mm EP’s which creates a long stack but it will get you to around F4. I’d reach out to Mark (CN Mazerski), he has been thru this before and gave up on SCT’s as the view was not bright enough when using an NVD. If you have an a AG power newt (F4 newt supplied with an ASA reducer) you can start at F 4 but can insert the ASA reducer to run at F 2.8. https://www.teleskop-express.de/shop/product_info.php/info/p4611_Boren-Simon-8--f-2-8-PowerNewton-Astrograph---Carbon-Tube.html With a 3 nm H-alpha filter you need all the speed you can get in your bortle 8/9 environment. The advantage is that you can insert a Barlow into the power newt to increase the focal length. It’s aways easy to make a scope slower then faster. The Barlow will cover the ranges the reduced SCT would reach. In summary it’s hard to have a single scope that’s covers visual and NVD usage cases. I would split them out as a power newt scope is a lot less then the above scopes you have mentioned, you could buy that and decide if you needed to go with an SCT for visual. The reason I suggest this is that NVD users I have talked to have the complete range of scopes from Takahashi etc (Even more then @JeremyS 😃) and in then end they sold them all as they just used a power newt. They also sold a large amount of there glass collection as well. For visual usage I’d go with the Mewlon as for non DSO work as the smoother mirrors would be a main advantage however it’s not as BV friendly as the SCT’s. A good thread to read would be: What is the Ideal set of equipment for Night vision Astronomy?

Me too. The LZOS has 220 mm of back focus making them very BV friendly and cool down is not much slower then my 4”. To be honest set up time compared to the 4” is only a couple of more minutes that I’ve not used the 4” in months. BV last week on the moon was very rewarding.

Carrying on the APO action, here is my LZOS getting frosted up: By the way first time out with BV's, no GPC required at all to gain focus with UFF 10 mm and 24 mm UFF. All very good! A little later A little bit latter Look ma no dew!

This is quite a complex subject for instance take Barnard loop, this requires a dark site (at least +21 SQM) and H-Alpha filter to really see. Aperture will not help you, all about contrast. So what type of objects do you want to apply this calculation too, are you including or excluding extended objects like those found in the sharpless catalog?