Rob_UK_SE

If you have the 6nm OIII-CCD version, your filter really targets the 501nm OIII line, but not the 496nm part. It is much more narrow/aggressive and therefore less suited to visual observation.

I have found the Bob’s Knobs springs to be really good and certainly stiffer than the standard Meade and Sky Watcher offerings. Due to their website, I’m never clear about Rother Valley Optics’ stock levels, but this is their link as they appear to be the only UK supplier offering them at the moment: https://www.rothervalleyoptics.co.uk/bobs-knobs-meade-lightbridge-primary-springs.html The last set I ordered were imported from the States and did arrive within a couple of weeks. This is the direct link (option D): http://www.bobsknobs.com/Newt/page45/NewtPri.html

Like so many, I also started with a 10” solid tube Sky Watcher. It was my first ‘manual’ large scope having moved away from a Celestron CPC925 that I was finding too heavy to regularly move to a darker observing location (it wasn’t really possible to observe from home at that time). Considering the price I paid for the SCT setup, I couldn’t believe how well the 250px resolved detail and gave views with, perhaps, slightly improved contrast too. I sold the Celestron kit a few weeks later. The only things upgraded on the 250px were the azimuth bearing to a roller type, some Bob’s knobs for the secondary and stiffer springs for the primary. I still think that they are terrific telescopes - especially for the price. However, this was also around the time that I joined Stargazerslounge (2011) and started to discover the great lure of larger telescopes. Amusingly, I thought my 10” Sky Watcher was a really big scope, but after my first experience of Steve’s old 16” lightbridge it well and truly left me with aperture fever! After almost moving up to a 14” Sky Watcher (consulting with many helpful people on this forum at the time), I ended up realising that it would be too heavy -for me- to comfortably move around and transport in the car. Instead, I purchased a 12” lightbridge. The 12” really did take things up a level and gave me breathtaking views which I will always fondly remember. My first time seeing M13, at higher magnification, from a dark location was particularly memorable. The lightbridge was supplied with a reasonable focuser, roller bearing and decent collimation screws. All that was required were some Bob’s knobs for the secondary and a Telrad... or so I thought! I had not realised the challenges of balancing a lightbridge when using heavy eyepieces. My 31N and 17E made it impossible to observe near the ecliptic without the scope becoming an unintended goto and deciding to ‘reset’ back to the horizon! Powermating any of my eyepieces was not an option at lower altitudes. This led to all sorts of attempts at securing counterweights with my preferred solution being taxi magnets holding dumbbell weights ... all very ‘low tech’ stuff. A few years past and we started a family. Observing took a bit of a back seat - sleepess nights continued, but not under the stars. I kept some of my eyepieces, but sold the telescopes due to the spare room being converted into a nursery. In addition to parting with the 10” and 12” dobs, I also foolishly sold my much loved TeleVue 102 refractor and I still very much regret it now! Anyway, moving forward a few years and I returned to the Astro game deciding that it could be a shared family experience too. A 300p flextube was purchased and I was delighted with it (as were the family). A couple of enhancements to the focuser and a homemade dew shield (which did indeed look suspiciously like a camping mat) and I was set. However, the weight proved a little too much for me to comfortably move around (following an injury) and I found myself purchasing my current dob - a 12” Explore Scientific ultralight II. Apart from the weight, I thought the 300p flextube was an excellent telescope for the money. It would often not even require collimation adjustments between sessions - even though I always checked. The flextube stems is very well designed. I don’t see too many of the ES ultralight dobs around. This is a shame because I have been really pleased with mine. I consider it to be the answer to many common issues with mass produced dobs - even though it is, itself, a mass produced dob. The first ES ultralights were probably released too early as they were littered with problems, but ES appear to have resolved most of these now. This scope can go in the car boot without having to put down the rear seats and this has been a real game changer. If only the ES 16” ultralight was slightly less expensive. As I read this back I can see that my attempt at a brief summary has turned into a right old ramble. Thank you for the trip back down memory lane and for letting me share a bit of nostalgia with you all!

If a budget allows for it, the Astronomik and Tele Vue filters are superb and will show both greater nebulosity and tighter stars. The Baader is close, but -for me- the contrast wasn’t quite as good (albeit very close). However, all of these premium filters are rather expensive and require sufficient aperture to make the most of them. Personally, I wish that I had been able to invest in premium filters from the start as it would have been cheaper in the long run, but I do also appreciate that this is not always possible.

I echo everything that has been said already about the Astronomik and Baader filters. I currently use the Astronomik one, but owned the Baader before that. My only suggestion is on the basis that you will -probably- use an OIII more frequently with lower to medium power eyepieces. I would therefore very much recommend investing in a 2” model - assuming your lower power eyepieces have 2” barrels. For me, the Veil nebula was my main motivation for justifying the 2” model and I have not been disappointed with its performance. The filter is used every session in the summer months (for both parts of the Veil and M27, in particular). It‘s utilised for different targets in the winter such as M97. Even good ol’ Orion takes on quite a different character and nebulosity when observed through an OIII filter.

I think that your suggestion of either a 200p or 250px are both great options. They are very competent telescopes -to start with- and both could be upgraded if you ever wish to with stiffer springs, different finder, focuser, different azimuth bearing etc. They also both really open up the possibilities of seeing many more faint fuzzies! A 10” dob can be considered a lifetime telescope. The speed in which an 8” or 10” solid tube dob can be setup ready for observing is also ideal. I regularly observe with someone that uses the Bresser 10” and they are setup ready to go in about 5 minutes while I am still very much ‘assembling’. If you can work to the top end of your budget and manage the size/weight (the Sky Watcher base is both bigger and heavier than other brands), I would recommend a 250px. This is assuming that you can find one in stock or don’t mind waiting. If you think that may, in the future, upgrade the focuser, springs etc it might be worth saving for the Bresser instead which could be cheaper in the long run. From memory, the finderScope supplied with Skywatcher is better (in my opinion) than the Bresser which has a smaller aperture. Having owned a 250px (albeit about a decade ago) and comparing those memorable views to a Bresser 10”, in my opinion, the optics are pretty much on par with each other. Synta, who distribute Sky Watcher telescopes, are very consistent with their newtonian mirrors. If correctly stored and cared for, the coatings should last a very long time indeed. While there is quite a learning curve to becoming familiar with the constellations and DSO locations, this is also part of the fun. Below are some useful links to star charts to help you find those fuzzies without goto 😄. Monthly updated Sky maps: http://skymaps.com/downloads.html Messier charts: http://www.custerobservatory.org/docs/messier2.pdf Cadwell objects: https://sherwood-observatory.org.uk/astronomy/finder-charts/caldwell-finders

On the occasions that I have used my scopes standing up, I have found a trekking pole really useful to steady myself. Holding onto the back of a garden chair can also really help. As I try to observe with a small towel or blanket over my head and/or a hood up in the winter (to block out extraneous light and maintain dark adapted vision) I find sitting down essential to avoid embarrassing balance issues!

I use the 21, 13, 8 and 6... I prefer to see a clearly defined field stop so it’s eye cup down for me. With the eye cup raised I have to push my eye right into it. I have experienced discomfort due to pressure around the bridge of my nose when trying to take in the full 100 degrees this way. For some reason, the eye relief also feels a little tighter on the 6mm, but it is manageable. The 13mm and 8mm are, for me at least, very comfortable with the cup down. My preferred technique is to lightly touch my eyebrow at the top of the cup (12 o’clock position). It is surprisingly easy to hold your eye position when seated for extended periods this way - including when working at smaller exit pupils. A positive of the eye cup up is reducing the chances of reflections and extraneous light. For this reason I will occasionally raise it to improve contrast/scatter on dim DSOs.

I believe your tripod is rated for payloads of approximately 9kg. The pillar is 5kg and your GP2 is about 4kg (excluding counterweights). Not knowing your scope, I am assuming that it probably is around 8kg (calculated based on a Bresser 5” 1200mm or similar). Taking into account the counterweights too, I would say that you are right on the limit of your tripod’s payload with a 5” achro and would recommend being cautious about adding a pillar too. As the legs on your tripod work on friction, it is slippage or leg failure you have to be mindful of.

I have not had any issues with movement from the 16” extension pillar once the bolt is tightened from under the tripod (I am using a Berlebach uni 18). It feels very secure. As far as I am aware, the pin is mainly intended for lining up north on equatorial and/or motor driven mounts. It’s not really for added security. I would, however, check on the maximum load of your tripod as the extension pillar does add a considerable amount of weight. The positive of this is increased stability, but it will be much more demanding on your tripod. You also have to carry the mount fixed to the pillar (if you are moving it) which further increases the weight of your rig.

Thank you, Don, for this helpful advice and also for your great insight into the Ethos range. I was surprised to hear of the differences between the 4.7mm and 3.7mm. I would very much like to observe through one (or both) of the Ethos SX for Uncle Al’s ‘Spacewalk Experience’ of the lunar module simulator. It sounds the 3.7mm is very much the one to have. Perhaps one day. ...hopefully I haven’t done the wrong thing! I ended up placing two orders yesterday morning. One was for a 30mm XW (following Don’s suggestion to acquire this focal length again) and the other for a 10mm XW. Both should be arriving today. I found a good price on the 30mm XW (£270), but couldn’t find the 30mm APM available anywhere in the UK - just from APM directly or from other suppliers in Germany. 365Astronomy may be having an eyepiece clear out as they are selling off some of the XWs, including the 10mm, for £210. I would have loved to have a full set of green and black (adding the 10mm Delos and 31mm Nagler again), but this is not possible at the moment.

The larger case is a Peli 1500. The internal measurements are: 435mm (length), 292mm (width) and 155mm (depth). The other case is a Peli 1300 which is now being used for a Telrad and collimator.

the 13mm Ethos is certainly my most used and the one I find easiest to take in the entire 100 degree field of view. I have directly compared it to the 13mm APM and found that they were very close indeed. For me, at least, the benefits of the Ethos were the eye cup (I found the APM one slightly less comfortable and needed to fold it down), slightly improved transmission and contrast as well as stars being sharp across the full 100 degrees. I would say the APM is a good 80-90% of the Ethos. If I ever had to replace it, I would probably buy the APM and be very content. I have made many changes to my eyepiece case/s over the years, but the 13mm has always been a constant. The images below are from 2012, 2016 and 2019 (before I got the 6mm Ethos from FLO). The 13mm Ethos has survived all major changes... so far.

When travelling to a darker location I try to adopt a ‘less is more’ approach and only take kit I know that I will use. In a funny sort of way, I feel that this actually improves my quality of life as I don’t have to deal with too many cases and more frequent trips back to the car. However, an observing chair is always a must -for me- as I like to spend quite a long time on each target, attempting to tease out detail. I also find a chair much more relaxing when observing at smaller exit pupils. Having previously had back problems, a riser base for my Telrad certainly improved things quite a lot - particularly when observing around the zenith. A flask of hot blackcurrant juice (Ribena) is very welcome, too, when things get a little colder.

I use a Geoptik bag and have been pleased with the protection and plushness of the internal padding. This one is suitable for 4” scopes with focal lengths up to 750mm: https://www.rothervalleyoptics.co.uk/geoptik-padded-case-for-100mm-refractors-f750.html This is for focal lengths up to 1000mm: https://www.rothervalleyoptics.co.uk/geoptik-padded-case-for-100mm-refractor-f1000-ota-neq6avx-tripod.html ...depending on how close your scope’s length is to 800mm. Rob

Thank you for these suggestions. John, it’s interesting to read that you tend to stick with your Ethos set for the 12” dob. I was assuming that your XWs might have some benefits in the dob too (in terms of light transmission, scatter control, object framing etc.)? I have certainly been very pleased with the Ethos quartet and don’t plan to part with them - especially for DSOs. I think we are all, to some extent, eyepiece addicts on this forum! Don, I have checked the magnification steps, based on your suggestion, and can see that the biggest gap does indeed appear to be between the 13mm and 8mm Ethos. In the 12” the spacing is 73x between these two; it is 43x in the 130mm APO. Given the current UK price for Ethos I can’t -regrettably- stretch to a 10mm now, but could go for an XW, Morpheus or similar. Reflecting on this focal length a little more, in the 12” it would result in 152x (2mm exit pupil) and 92x in the 130mm APO (1.4mm exit pupil). I think both of these magnifications and exit pupils would be useful. The views of both parts of the Veil (in the 12”) are lovely, but it does struggle -even with the 21mm Ethos- to frame the eastern part properly. When using the 21mm in the 130mm APO the exit pupil is down to 3mm which may well account for the dim view which isn’t nearly as immersive. One of my biggest regrets in this hobby was selling my 31mm Nagler, but it is now too expensive to be replaced for only occasional use. Further to your suggestion and linked to the 10mm, perhaps a 30mm XW or APM UF is indeed needed too? With an exit pupil of 6mm it could still be useful (at dark sites) with the dob. Baz, your point is one I have wrestled with for quite a while in this hobby - wanting to spend more time observing than auditioning eyepieces. Decisions, decisions...

Hello all, I am toying with the idea of filling in some gaps within my current eyepiece collection. For some time I have tried to simplify things by owning fewer eyepieces that would, in theory, spend more time in the focuser. The current focal lengths are 21mm, 13mm, 8mm and 6mm plus a Nagler zoom (for higher power in a refractor). The scopes used are a 12” f5 dob and a 130mm f7 APO. Living relatively near to the coast, the atmospheric conditions can be quite unpredictable which has resulted in me wondering... should I ‘fine tune’ things a bit to achieve more optimum views? Excluding the 6mm, the 21/13/8 trio follows a spacing of 1.6, but -perhaps- I am trying to cover too much ground with just these focal lengths and two scopes. Have others (that have adopted 100 degree eyepieces) also ended up reducing their originally planned eyepiece spacing due to this? In summary, I am considering purchasing a 10mm Pentax XW to both try out this much praised Pentax range as well as to start filling in the current gaps. Is this unnecessary madness, a case of ‘eyepiece addiction’ or have others ultimately found it useful to have closer focal lengths? Is there a general consensus on a ‘goldilocks’ (not to short/large) eyepiece spacing when you use more than one scope? Thanks. Rob

How time moves on... I haven’t posted for a while, but regularly read and appreciate the treads here. When I started this discussion (8 years ago) I really wanted to get the largest aperture I could afford. I had most certainly caught the ‘aperture bug’ - particularly after seeing Steve’s (Swamp Thing) old 16” Meade which was my first experience of a large scope. I was sold on larger aperture immediately. My experience with a 12” lightbridge and then a Sky Watcher 300p Flextube -that followed- confirmed that I very much enjoyed the views, but still needed to change my approach. Instead of the biggest aperture I could afford, it became a priority to find the biggest aperture I could both comfortably and regularly move. I missed too many opportunities to observe due to transport issues (... and a bad back). After a period without a big(ish) dob, I settled on a 12” Explore Scientific Ultralight II and a 130mm APO refractor which are, for me, much more manageable. Interestingly, the refractor sees much more use than the dob. An Orion Optics (UK) VX14 would be perfect (for me), but is out of my price range at the moment. I would love to own and regularly observe through a 14” or 16”, but the Chinese made ones are, regrettably, too heavy for me. However, I bet galaxy hunting is superb through your scope, Paul. Rob