Hisanori
31-07-2017, 01:23 PM
Hello
I leave some note on my recent observation session since I'm very happy with acquisition of Takahashi TSA-120 from my friend Ian. (It was my milestone decision eating up my next few years telescope budget..!) :question:
Monday last week, I took both of my Takahashi TSA-120 and Meade LX200R 10' (I've got from Pete last year. Bit heavy but very very nice scope.. comma free, sharp to the edge of FOV) set up side by side to compare a difference on visual performance (at least I tried if I could :astron:) I chose my usual dark site in the somewhere North and started to set up just before the sunset and stayed around about 4 hours or so. A mid-day's high was around 20 degree and drop to a single digit :rolleyes: during night. It may be a bit harsh to SCT. Not even talking about I don't have any fan attached to clear hot air in the baffle of my LX. As expected TSA started to perform within a half hour or so, on the other hand LX struggle to stabilise for about 2 hours. I tested Jupiter first then Saturn. I should say the seeing was not very best that night but could be used 6 mm eyepiece comfortably on TSA (150x), and 12.5 mm on LX (200x).
My high power eyepiece range at this moment is Vixen NLV4, SLV6, LVW8, and Takahashi LE7.5 & LE12.5. I attached LVW8 first on TSA, and relatively being surprised with a good contrast and a wide FOV plus comfort. LE7.5 was brighter and slightly better contrast but probably due to the seeing condition an extra 0.5 mm didn't provide any significant advantage to LVW. Next level of my EP was SLV6. Although I'm not fond of this eyepiece (lacking contrast I feel), the 6 mm was the best magnification I could get that night on TSE.
On LX, initially I tested LVW8 but was too powerful then settled with LE12.5. A diffraction ring is concentric. I don't believe a collimation was out. The first 2 hours it presented a clear disturbance from the tube current (and perhaps seeing condition in certain extent) showing images dancing every half second. Within about 2 hours the images started to be stabilised. I could get slightly larger magnification than TSA, but in terms of the contrast and stability of images (hard to describe... TSA is sharper and crispy, and dead solid stable image) LX couldn't beat TSA. A potential solution to improve my LX could be further fine tuning on collimation. Last year, Pete took the OTA to Bintel to be collimated before selling to me. But it may be needed another tuning by now to maximise it's potential.:thumbsup:
It was a moonless night, therefore I turned the scopes to few typical deep sky objects. I tested Eta Carinae Nebula, Omega Centauri, 47 Tucanae, Trifid Nebula, Jewel Box Cluster, NGC3532, Tarantula Nebula.. I had a light pollution on the South from Sydney.. therefor some low hanging objects were not clear. I should say among all Omega Centauri was the best target that night. I used LVW42 on LX to observe this (it should be 60x), and used LVW17 (53x) on TSA. I also used Moonfish 30mm interchangeably both scopes. Although sharpness of stars on TSA was incredible :eyepop: (pin sharp!!!) amount of light gathered on LX's 10 inch mirror exceeded TSA :party:. Because of brighter image of the object, LX's image is appeared to have better contrast. Overall I was impressed with LX200R's performance on deep sky objects which was little unexpected (after sacrificed my large budget on TSA), but the same time I was also pleased with my SCT's performance.;)
Those comments are visual impressions only and nothing scientific (and pardon me I'm still early days on astronomy!!! :rolleyes:). During the observation, I have also swapped eyepieces and diagonals between TSA and LX to make sure any difference in the performance were not inherent to those parts.
I used a tracking mount - Vixen Sphinx for TSA-120, and NEQ6 Pro for LX200R 10'. Dew was absent during my observation, it was quite dry night, just needed a metal Astrozap dew shield for LX, and extension of standard dew shield on TSA. I didn't use dew heaters.
I think LX's performance should be increased if I attach some ventilation fan. Also I was told leaving OTA up on the focuser facing sky (without eyepiece) to let a warm air out. I could try this next time.
Cheers :hi:
Hisanori
I leave some note on my recent observation session since I'm very happy with acquisition of Takahashi TSA-120 from my friend Ian. (It was my milestone decision eating up my next few years telescope budget..!) :question:
Monday last week, I took both of my Takahashi TSA-120 and Meade LX200R 10' (I've got from Pete last year. Bit heavy but very very nice scope.. comma free, sharp to the edge of FOV) set up side by side to compare a difference on visual performance (at least I tried if I could :astron:) I chose my usual dark site in the somewhere North and started to set up just before the sunset and stayed around about 4 hours or so. A mid-day's high was around 20 degree and drop to a single digit :rolleyes: during night. It may be a bit harsh to SCT. Not even talking about I don't have any fan attached to clear hot air in the baffle of my LX. As expected TSA started to perform within a half hour or so, on the other hand LX struggle to stabilise for about 2 hours. I tested Jupiter first then Saturn. I should say the seeing was not very best that night but could be used 6 mm eyepiece comfortably on TSA (150x), and 12.5 mm on LX (200x).
My high power eyepiece range at this moment is Vixen NLV4, SLV6, LVW8, and Takahashi LE7.5 & LE12.5. I attached LVW8 first on TSA, and relatively being surprised with a good contrast and a wide FOV plus comfort. LE7.5 was brighter and slightly better contrast but probably due to the seeing condition an extra 0.5 mm didn't provide any significant advantage to LVW. Next level of my EP was SLV6. Although I'm not fond of this eyepiece (lacking contrast I feel), the 6 mm was the best magnification I could get that night on TSE.
On LX, initially I tested LVW8 but was too powerful then settled with LE12.5. A diffraction ring is concentric. I don't believe a collimation was out. The first 2 hours it presented a clear disturbance from the tube current (and perhaps seeing condition in certain extent) showing images dancing every half second. Within about 2 hours the images started to be stabilised. I could get slightly larger magnification than TSA, but in terms of the contrast and stability of images (hard to describe... TSA is sharper and crispy, and dead solid stable image) LX couldn't beat TSA. A potential solution to improve my LX could be further fine tuning on collimation. Last year, Pete took the OTA to Bintel to be collimated before selling to me. But it may be needed another tuning by now to maximise it's potential.:thumbsup:
It was a moonless night, therefore I turned the scopes to few typical deep sky objects. I tested Eta Carinae Nebula, Omega Centauri, 47 Tucanae, Trifid Nebula, Jewel Box Cluster, NGC3532, Tarantula Nebula.. I had a light pollution on the South from Sydney.. therefor some low hanging objects were not clear. I should say among all Omega Centauri was the best target that night. I used LVW42 on LX to observe this (it should be 60x), and used LVW17 (53x) on TSA. I also used Moonfish 30mm interchangeably both scopes. Although sharpness of stars on TSA was incredible :eyepop: (pin sharp!!!) amount of light gathered on LX's 10 inch mirror exceeded TSA :party:. Because of brighter image of the object, LX's image is appeared to have better contrast. Overall I was impressed with LX200R's performance on deep sky objects which was little unexpected (after sacrificed my large budget on TSA), but the same time I was also pleased with my SCT's performance.;)
Those comments are visual impressions only and nothing scientific (and pardon me I'm still early days on astronomy!!! :rolleyes:). During the observation, I have also swapped eyepieces and diagonals between TSA and LX to make sure any difference in the performance were not inherent to those parts.
I used a tracking mount - Vixen Sphinx for TSA-120, and NEQ6 Pro for LX200R 10'. Dew was absent during my observation, it was quite dry night, just needed a metal Astrozap dew shield for LX, and extension of standard dew shield on TSA. I didn't use dew heaters.
I think LX's performance should be increased if I attach some ventilation fan. Also I was told leaving OTA up on the focuser facing sky (without eyepiece) to let a warm air out. I could try this next time.
Cheers :hi:
Hisanori